Postalcodes-ca

fixes a spelling/encoding error and removes the "L0V" FSA code for "Westminster Abbey" which seems fake

iterating over postal codes now returns the codes as strings instead of as objects, as a normal dictionary should

also made some properties private

added `postal_codes` which lets you look up full postal codes instead of just FSA codes

also a number of minor changes:

- made `FSACodeDatabase` look more like a Python dictionary by implementing `__len__()` and `__iter__()`
- added a few extra properties like `.fsa` to get the FSA of postal codes as a string.
- added tests
- added continuous integration on GitHub
- better documentation in the readme

renamed CA.txt to CA.tsv and updated the readme to reflect that

this is the first release