editor window title improvements

Shows the project name in the window title (good to differentiate multiple instances of Godot with different projects loaded).

Clears the previous scene name from the window title when creating a new scene.
add display/resizable support to Linux

add display/resizable support to Linux
Merge pull request #315 from adolson/patch-2

add display/resizable support to Linux
Merge pull request #272 from adolson/patch-1

editor window title improvements
Merge branch 'master' into notification_script_var