Known Bugs:
 * Dot is not always restored properly (e.g. after closing file)
 * FS broken in loops - inserts even if search failed
 * Strange behaviour after loop interruption (e.g. "<%a>")
 * Null-byte in strings not always handled transparently

Features:
 * Patch Scintilla for TECO-style control code echoing (^X) instead of mnemonics
 * Progress indication in commandline cursor
 * catch OOM errors (can happen easily due to infinite loops)
 * undo-tokens per char limit (additional infinite loop safety)
 * Function-key support
   * generic function-key substitution, or
   * function-key encoding (e.g. Page-down -> ^FPD)
 * extended Q-Register namespace
   * 2 char q-registers like in Troff (e.g. "Q(xy")
   * arbitrary length names (e.g. "Q$xyz$", see ITS TECO)
   -> Macro libraries
 * Q-Register aliasing/linking
 * EC command
 * command-line push-down mechanism
 * TECO syntax highlighting
 * multiline commandline
 * improve GTK interface

Documentation:
 * Code docs (Doxygen)
 * Manpage
 * Language reference?
 * Command reference