Require project root for workspace and files only
Add favorites list

Fix #24
Fix #39
Fix #40
Add favorites history
Optimize project root lookup and caching
Improve handling empty favs list
Improve first fav creation
Improve favs
Reload workspaces
Improve workspaces handling
Fix syntax
Fix typo
Add change active favorite event
Use selected fav dir for adding
Improve existing favs detection
Improve error messages display
Rename favorites to bookmarks
Improve workspace loading
Add new/blank workspace key in buffer list
Remove events mechanics (not necessary yet)
Simplify workspaces and files cache opts