Initial swift support

This is a first stab add adding Swift support... not thoroughly tested yet. Some things that need to be done:

- [x] Nested comments
- [x] Test Generics
- [x] Add Contributor changes
- [x] Shorten example
- [x] Remove JS leftovers
- [x] Split lines that are > 80 chars
- [x] Remove empty category
- [x] Remove relevance
- [x] String interpolation
On 06/16/2014 12:48 PM, Chris Eidhof wrote:
> Yes, it can return any kind of expression... is there a good way to
> write that? Or just enumerating the possibilities?

In this case, it's probably okay to just list all the things, there 
aren't that many yet (I doubt you could define types and functions 
within substitutions).

In more complex cases it's usually done by defining a dedicated mode 
containing all embeddable syntactic elements and concatenating it with 
the main list and with whatever submode wants it. Look for 
RUBY_DEFAULT_CONTAINS in ruby.js for example. But again, I don't think 
we need it here yet.