refactor: restructured and cleaned up text buffer stuff

	modified:   editor.rb
updated documentation

	modified:   doc/internals.md
refactor: separated source code into multiple files

Also renamed executable to jedi.
And created script to reassemble the files into one.
bugfix: better handling of empty replace strings

Input to ask() is now an optional hash of flags.

	modified:   antsy.rb
	modified:   filebuffer.rb
feature: yes-to-all option for search and replace

	modified:   antsy.rb
	modified:   filebuffer.rb
bugfix: wasn't handling viewmode properly

Tested for editmode/viewmode wrong.

	modified:   editor.rb
bufix: opening a new buffer crashed the editor

Didn't update function call to ask() in a couple places. Fixed.

	modified:   bufferslist.rb
	modified:   editor.rb
bugfix: all_on_one needs to force redraw of info line

needed to all write_info_line to force redraw

	modified:   bufferslist.rb
	modified:   filebuffer.rb
bugfix: correct column placement in split screen mode

Wasn't handling column shifts correctly.

	modified:   antsy.rb