Clean up the osx enum_* modules.

Please do not review/merge, for now this is a placeholder PR so that I can verify. It will be closed momentarily.

This PR does a bit of touch-up work on some of the osx post modules:

- Removes required/default pattern for enum_adium, since it seemed restrictive
- Dries up a whole bunch of code in enum_osx.rb
- Fixes a couple of places where `cat ...` was used instead of `Post::File#read_file`
- Kills some unnecessary comments/texts in different places
- Fixes some typos

Verification:
Go through these steps with a shell session on OSX 10.8 or 10.9:

- [ ] enum_adium works as expected
- [ ] enum_airport works as expected
- [ ] gather/hashdump works as expected
- [ ] enum_osx works as expected

Now with a java meterpreter session on OSX 10.8 or 10.9:

- [ ] enum_adium works as expected
- [ ] enum_airport works as expected
- [ ] gather/hashdump works as expected
- [ ] enum_osx works as expected

Now with a shell session OSX 10.7 or below:

- [ ] enum_osx works as expected
- [ ] gather/hashdump works as expected