Theme fixes

- Fixes pathbar button display in Adwaita
- Reverts special icon names for toolbar items (it's fixed in Mint-X now, and this way other themes aren't left hanging)
- Restore name of recent icon so it's a common theme name (did not display in other icon themes)
- Move recent button down to just above File System.  It still looks sorta bad, but we can make a better one that still looks good everywhere else (maybe a grey version of what's there now?)