Improve multibyte handling especially for g:EasyMotion_key !

Relate: #16
Improve readability and add NOTE for multibyte handling
Perform refactoring of marker substitution section
Fix multibyte handling for EOL and bland line
Unify the way to get marker_char from marker_chars
Fix to get target_char correctly

Get from marker, modified line, instead of original target line.
Test: add vim-vspec test for default word motion(w/b)

Relate: #88
Merge branch 'improve/test' into master
Improve helper#is_folded()
Fix typo
Escape '&' for substitution
Merge branch 'handle/multibytetargetkey' into master

close #16
Doc: add non-ascii, multibyte keys example

Relate: #16
Improve & Refactoring multibyte handling
Improve <Space> expression
Fix typo
Merge branch 'master' of https://github.com/Lokaltog/vim-easymotion

Conflicts:
	autoload/EasyMotion.vim