Ticket #1743: remove limit of file size in mcedit.

Initial commit: refactoring:
  * (edit_load_file_fast): always load whole file.
  * (edit_load_file): don't ignore result of edit_load_file_fast().

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_move_updown): avoid extra search of multi-byte character start.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Start of edit buffers refactoring.

Move buffers to separate class.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Refactoring of init/clean editor buffer.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Refactoring editor buffer functions of get bytes/symbols.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_complete_word_cmd): fix get word from buffer.

(edit_get_match_keyword_cmd): likewise.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_buffer_read_file): new editor buffer API.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_buffer_read_file): refactoring: return number of read bytes.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_buffer_write_file): new editor buffer API.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_buffer_write_file): refactoring: return number of write bytes.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
New editor buffer API to insert character at cursor position.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
New editor buffer API to delete character at cursor position.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_cursor_move): refactoring using editor buffer API.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Use GPtrArray to store editor buffers.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Rename edit_buffer_t members.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(edit_indent_width, edit_insert_indent): move to wordproc.c and make static.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
A lot of type accuracies.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(get_paragraph): refactoring.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Refactoring: move members from WEdit to edit_buffer_t and rename related functions:

WEdit::last_byte -> edit_buffer_t::size
WEdit::total_lines -> edit_buffer_t::lines
WEdit::curs_line -> edit_buffer_t::curs_line

edit_count_lines() -> edit_buffer_count_lines()

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Refactoring: rename functions of getting BOL and EOFL:

edit_bol() -> edit_buffer_get_bol()
edit_eol() -> edit_buffer_get_eol()

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>