View > Show Developer Tools should bring it to front if already open

[peterflynn]

Steps:

1. View > Show Developer Tools
2. Switch back to main Brackets window. Resize it so it totally covers the Developer Tools window.... do a bunch of work and gradually forget that you have Developer Tools open.
3. View > Show Developer Tools

Results:
Nothing appears to happen. Click it again, get frustrated... eventually realize the window is already open, just hidden behind the main window.

Expected:
Should bring Developer Tools window to the front if it's already open.
(Although maybe if it's already open and focused, then this menu item should close it instead?)