Promoted the clang plugin's _NameFilter to dxr.filters.
Fixed _NameFilter to not freak out if its needle type isn't in the results.
Basic support for Python class and function definitions.
Surface indirect overrides in "overrides" queries. Ref bug 1030312.

Build the inverse of the overriddens graph during the whole-program pass, and look at it when generating needles.
Remove unused imports.
Make Config no longer dependent on filesystem objects. Ref bug 959728.

This saves us a file write during SingleFileTestCases.

build_instance will likely change to take a dict-like object later, making it even more manipulable, once we've converted to configobj.
Fix config bug wherein specifying `*` for `enabled_plugins` or `disabled_plugins` wouldn't take all the plugins into account.

Also remove the last vestiges of a single plugin folder. You'll need to remove references to plugin_folder in your config file if you had them and instead register your third-party plugins using setuptools entrypoints, as described at http://dxr.readthedocs.org/en/es/development.html#registration.
Renamed _NameFilter to NameFilterBase.
PEP8 imports in python/indexers.py.
Removed extraneous makefiles in the Python plugin tests.
Broke out the Python filters into their own module.
Import NameFilterBase from dxr proper, not the clang plugin.
Merge very basic support for Python indexing: functions and types (classes) so far.
Make python plugin's all_needles method private.

After all, it's not supposed to be called from the outside.
Add entry point dance to the Development troubleshooting section.
Remove some debugging prints that got away.
Rename _CFilter to _NameFilter for consistency with _QualifiedNameFilter.
Take C++'s implicit upcasting into account for "callers" searches. Ref bug 1030312.