* You can now set a per-file tab style, that differs from the defaults established
  in the ED hook.
  This is important especially since we do not yet support per-project .teco_ini
  scripts where you could establish differing policies depending on the VCS repository.
  (The latter would be easy to implement, but we cannot currently easily extend the
  existing ED hooks.)
* It's unlikely that files contain an ASCII 27, but not impossible.
  Therefore we now use ASCII 0 (^@) as a terminator.
  This indeed be safe under UNIX.
  Even better would be a string building construct for escaping ASCII 27 ($), though,
  as that would work with arbitrary bytes.

The macro prefix was changed from ^F to ^K.

* Curses: "icons" have also been added

This previously highlighted little more than embedded Javascripts.

* ALL keypresses (the UTF-8 sequences resulting from key presses) can now be remapped.
* This is especially useful with Unicode support, as you might want to alias
  international characters to their corresponding latin form in the start state,
  so you don't have to change keyboard layouts so often.
  This is done automatically in Gtk, where we have hardware key press information,
  but has to be done with key macros in Curses.
  There is a new key mask 4 (bit 3) for that purpose now.
* Also, you might want to define non-ANSI letters to perform special functions in
  the start state where it won't be accepted by the parser anyway.
  Suppose you have a macro M→, you could define
  @^U[^K→]{m→} 1^_U[^K→]
  This effectively "extends" the parser and allow you to call macro "→" by a single
  key press. See also #5.
* The register prefix has been changed from ^F (for function) to ^K (for key).
  This is the only thing you have to change in order to migrate existing
  function key macros.
* Key macros are enabled by default. There is no longer any way to disable
  function key handling in curses, as I never found any reason or need to disable it.
  Theoretically, the default ESCDELAY could turn out to be too small and function
  keys don't get through. I doubt that's possible unless on extremely slow serial lines.
  Even then, you'd have to increase ESCDELAY and instead of disabling function keys
  simply define an escape surrogate.
* The ED flag has been removed and its place is reserved for a future mouse support flag
  (which does make sense to disable in curses sometimes).
  fnkeys.tes is consequently also enabled by default in sample.teco_ini.
* Key macros are handled as an unit. If one character results in an error,
  the entire string is rubbed out.
  This fixes the "CLOSE" key on Gtk.
  It also makes sure that the original error message is preserved and not overwritten
  by some subsequent syntax error.
  It was never useful that we kept inserting characters after the first error.

It's not a real Lexilla lexer, but simply styles the document
once in lexer.set.git in order to highlight comment lines.

* ^Uq however always sets an UTF8 register as the source
  is supposed to be a SciTECO macro which is always UTF-8.
* :^Uq preserves the register's encoding
* teco_doc_set_string() now also sets the encoding
* instead of trying to restore the encoding in teco_doc_undo_set_string(),
  we now swap out the document in a teco_doc_t and pass it to an undo token.
* The get_codepage() Q-Reg method has been removed as the same
  can now be done with teco_doc_get_string() and the get_string() method.

* ^E is heavily overloaded and can also be used to check whether a given index is valid
  (as it is the same that most movement commands to internally).
  Besides that, it is mainly useful for interfacing with Scintilla messages.
* EE takes a code page or 0 for ANSI/ASCII.
  Currently all documents and new registers are UTF-8.
  There will have to be some kind of codepage inheritance and a single-byte-only mode.

* This is optimized for Groff, but works for Heirloom Troff and Neatroff as well.
  Currently, the Heirloom and Neatroff requests are just added ontop of the Groff
  ones. Theoretically, we could also try to separate the keyword lists into
  a base K&R set with Groff, Heirloom and Neatroff ontop.
* The lexer necessarily has many restrictions, as Troff is fundamentally unparseable
  (like classic TECO) and needs a lot of per-request knowledge.
* The "*.mm" extension has been removed from the lexers/cpp.tes.
  I don't know what language this was for, and I prefer `*.mm` files
  to be considered Troff.
* Temporarily changed the lexilla submodule URL.
  The corresponding Lexila lexer is in the process of being upstreamed.
  Once it is, I will probably revert the submodule to the official repository,
  as the "troff" branch is not stable (can be rebased).