Introducing a Scopes Mapper to map from RA scopes to TextMate scopes with fallbacks.
Current scopes defined:
```
['keyword.unsafe', ['storage.modifier', 'keyword.other', 'keyword.control']],
['function', ['entity.name.function']],
['parameter', ['variable.parameter']],
['type', ['entity.name.type']],
['builtin', ['variable.language', 'support.type', 'support.type']],
['text', ['string', 'string.quoted', 'string.regexp']],
['attribute', ['keyword']],
['literal', ['string', 'string.quoted', 'string.regexp']],
['macro', ['support.other']],
['variable.mut', ['variable']],
['field', ['variable.object.property']],
['module', ['entity.name.section']]
```
Need to complement with further fallbacks as some themes fail.
0ddf47a7ab