Known Bugs:
 * ??? Dot is not always restored properly (e.g. after closing file)
   need test case!!!
 * Null-byte in strings not always handled transparently
 * saving another user's file will only preserve the user when run as root
   (WON'T FIX!?)

Features:
 * 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, configurable
   * generic function-key substitution, or
   * function-key encoding (e.g. Page-down -> ^FPD), or
   * function-key to ASCII/UTF mapping (as command executes macro of the same name)
 * 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
 * modifier for toggling string building processing
 * simplify parser (static jump tables are unnecessary!)
 * ??? optional modified-detection based on hash sums ???
 * backup files
 * search and other commands can be significantly optimized:
   in batch mode, or in loops there is no need to rematch every character!

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