bugfix: fix problem with indentation facade

If a file with history is opened, and immediately we change the
indentaion facade, it does not apply to the current state (only to the
history).

Here's what was happening: the initial text state is not part of the
history, because when it is read in from a file, it hasn't changed
state from the previous version (probably).  Thus, if the current (from
file) state matches the "current" state in the buffer history, set the
current state to a clone of the buffer history current state.

	modified:   src/filebuffer.rb
WIP: mask works, but for fileaccessor stuff

	modified:   src/bufferhistory.rb
	modified:   src/fileaccessor.rb
	modified:   src/filebuffer.rb
	modified:   src/keymap.rb
mask works!  Now just need to test for irreversibility

	modified:   src/fileaccessor.rb
	modified:   src/filebuffer.rb
	modified:   src/textbuffer.rb
checking for reversibility. but what about regexp?

	modified:   src/bufferhistory.rb
	modified:   src/filebuffer.rb
made histories for mask

	modified:   src/filebuffer.rb
	modified:   src/histories.rb
alignment!  Not well tested...

	modified:   src/filebuffer.rb
	modified:   src/keymap.rb
better comments in utils.rb

	modified:   src/utils.rb
Some cleanup; untested.

	modified:   filebuffer.rb
bugfix: run startup scripts before parsing options

This will allow command-line options to override startup script stuff.
Only problem is that "portable" mode will still run startup script.

	modified:   editor.rb
Brought README up-to-date

	modified:   README.md