Improved style of the panel's buttons

- Grouped buttons in 2 groups (left and right)
- Removed the GIT version (It's quite useless have it always visible there)
- Replaced the "Report bug" label with a tiny bug icon (more space for core-features)
- Added "Report bug" even on not-inited repositories
- Moved the "Bash" button from the file-tree panel to the git-panel (on the right side)