Add sorter_ftime.
Fixed header status.
Merge pull request #324 from osyo-manga/add_sorter_ftime

Add sorter_ftime.
- doautocmd BufEnter, BufWinEnter.
- Improved on_cursor_moved().
- Added BufWinEnter.
Fix to use args on file/new & directory/new.
Add about args on file/new and more.

file/new, directory, directory/new
Merge pull request #328 from DeaR/fix-file/new

Fix to use args on file/new & directory/new.
- Added FAQ section for toggle sources.
- Improved check highlight.
- Improved sorter_rank.
- Improved cursor line behavior.
- Added test code.
- Improved cursor line behavior.
changed candidates pos
- Fixed file/new behavior.
- Fixed file/new.
Merge pull request #332 from basyura/changed_candidates_pos

候補の初期表示数を winheight(0) にする
- Fixed #331.