doc
fix subtle bugs related to issue #14

- fix repeat of f and t in visual-mode
- use v:prevcount in visual-mode f/t reset
reset() unmaps _all_ temp mappings to mitigate macro breakage / #21
basic test cases
tests for visual-mode
Merge branch 'test' of https://github.com/justinmk/vim-sneak into test

Conflicts:
	tests/test.vader