Add ability to search all files in the project

Adds a "Find in Project" option to the "Project" menu and a "search" function to the ProjectManager.  Regular expression and multiline queries are supported.  Clicking a result will open the file (if not open already) and move the editor's cursor to the appropriate line and column.  I have plans to make this a combination "Find / Replace in Project".  Let me know if you have any questions.
This check doesn't do anything useful, as far as I can tell. Even assuming the test is valid (why feed results in that don't have these values?), there's no way that they got those properties via their prototype, so `hasOwnProperty` is overkill.