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.
Haha.  The anonymous function used to exist in multiple places.  Looks like I forgot to move its contents into the outer function when sanitize_queries was created.  I'll correct for this.  Thanks.