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

Add folder icon
Implement branch folder
Implement branches.layout config option
Fix branch node ordering in Tree layout
Sort branch folder containing current branch correctly
- Add current getter method to BranchNode
- Implment a recursive findCurrent method on BranchFolderNode
Do not parse invalid branch name as branch folder
Expand current branch folder

Adds patreon links

Updates dependencies

Adds showWhatsNewAfterUpgrades setting
Removes messages.suppressUpdateNotice
Removes messages.suppressWelcomeNotice

Updates all the screenshots
Updates welcome & settings

Adds debug outputLevel

Adds settings for GitLens Results view
Adds layout settings for explorers
Adds not equals support
Updates README (wip)

Fixes settings migration

Rewords many settings

Moves settings images into a settings folder
Adds hover setting images
Updates dependencies