Use -style instead of the deprecated -fg/-bg/-attr
Use double quotes to ease shell commands usage

Close #17
Use constants FG,BG,ATTR instead of magic numbers
Allow themes to set pane borders
Add experimental "vim_statusline" themes
Rename theme vim_statusline.vim -> vim_statusline3.vim
Put extraction of vim stl colors into one function
Don't keep the completion function in plugin/
Rename vim_statusline* themes
Check vim's colorscheme defines StatusLine(NC)
Revert to *-bg/fg/attr for tmux 1.8 compatibility

Fix #23, #26
Update README for vim_statusline_* themes