Fugitive reltive functions

- Add GBlameA as customized Gblame, resize blame window to Author.
- In Gblame, `gf` to open git diff,
  `<LocalLeader>gf` open in new tmux window.
- AlterCommand "gits" to Gstatus.
Use t9md/vim-choosewin

Type `<C-W>/` to choose.
Use kana/vim-fakeclip