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.
I have come to Carat from Komodo Edit.  It supports searching through files and it remembers the types of files I wish to include / exclude.  I find this really useful.  Additionally, I frequently find myself repeating previous searches.  My current code saves query history (up to 20 I think), but this is not yet exposed in the UI.