Added custom metadata search to GUI
Don't include release year in output file name or media dropdown list if it is null

Made Movie.ReleaseYear nullable, added ToString() to Movie and TVShow, added ReleaseYearDisplayable property to Movie, and refactored TmdbPlugin.cs
Minor/ignore - Added region to Controller.cs
Refactored MediaPanel.cs
Allow FormMetadataSearch window to be resized
Automatically resize FormMetadataSearch when the value of the "search query" TextBox changes
Minor - Updated default size of FormMetadataSearch window
Added 2 letters of padding to FormMetadataSearch AutoResize() calculation
Updated TODO.TXT
Added root panel to FormMain to make future UI modifications easier
Added MenuStrip to FormMain
Added bdhero_gui_128.png to GUI project
Added SystemInfo class
Minor/ignore - Removed unused 'using' from IController
Added bdhero_gui_128.png to .csproj file
Added AboutBox
Updated AboutBox
Fixed AboutBox display
Bumped version from 0.5.9.0 to 0.6.0.0
Updated "Documentation" menu item text to "Online Documentation" in FormMain