Refactor directions to variables

refer to directions via functions in preparation of supporting hsplits

refs #21
adapt shrink/unshrink to support hsplits

refs #21
Merge branch 'master' into hsplit

Conflicts:
	autoload/accordion.vim
Fix merge errors
Document hsplit feature
Always return a magnitude from GetMovementDirection()
Properly detect size changes

fixes #32
Remove fenc from modeline

It causes errors when opening :help (due to clashes with 'nomodifiable')
Merge branch 'master' into hsplit

Conflicts:
	README.markdown
	autoload/accordion.vim