Project symbol import from 'ctags'

Summary:
I noticed that documentation said it is possible to have 'ctags' symbol import, so I hacked a quick version. I tested it on Python based project and successfuly imported symbols.

It is limited to classes right now, as the importer script complained about not-unique method names (there are a lot of 'get' & 'post' methods accross classes in my project).

If you would have any feedback about this, I would definetly try to wrap it up for possibly merging into main repository.

Test Plan:
Required 'ctags' tool (ctags.sourceforge.net/) Tested to work with version 5.8+ and didn't work with 3.x.

1. find . -type f '*.py' | ./generate_ctags_symbols.php > /tmp/symbols
2. ./import_project_symbols.php < /tmp/symbols

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: seporaitis, aran, epriestley

Maniphest Tasks: T1034

Differential Revision: https://secure.phabricator.com/D1995