Don't automatically delete Fugitive buffers

Not sure why I've deleted them before
GllogPatch shows log for current file
"close tab" mapping to `,w`
Remap Easymotion prefix from `'` to `;`

The 'mark' functionality broke after recent Easymotion update.
Remapped "git commit mode" to `,<space>`

Save is `<space>`, Commit is `,<space>` - they're related enough
Add 'todo.md' to .gitignore

I started to keep my local shortcoming todo list in the project dir
Less last messages in gitcommit

All should be obvervable without scrolling
Remap 'GlopenFromDiff' to Space
Close Tab mapping changed to `<leader>W`
GllogPatch additional mappings
Mapping to jump to previous/next commit in diff mode

* `,N` - Jump to next commit (in diff mode)
* `,P` - Jump to previous commit (in diff mode)
Added functions to view pull-request/commits between HEAD & origin

Also, some mappings changed:

* `,gh`  - Show last 200 commit of all files in new tab
* `,,gh` - Show last 200 commit of current file in new tab
* `,gp`  - Show pull-request summary between current branch and base br.
* `,gc`  - Show commits log between current branch and base branch
* `,,gp` - Show pull-request summary between current branch and origin
* `,,gc` - Show commits log between current branch and origin