Closes #51, Closes #167, Closes #270

Adds advanced.fileHistoryFollowsRenames setting
Adds commands to set rename following to the GitLens explorer

- Removes mix-tree support
  - Avoids nesting on the current branch
  - Caches basename
  - Replaces folder icons with theme icons
    - Folder icons will now follow the file icon theme used
  - Fixes minor nitpicks

Updates dependencies

Updates all the screenshots
Updates welcome & settings

Since git log --follow drops merges, -m --first-parent adds them back

Adds repo name to results if there is more than 1

Adds repository creation detection when there are no repositories

Resolves chcken/egg issue with tracker and git service