Added IPAddressType, refactored types
Add an ImproperlyConfigured exception.

 - To be used to signal when a type is being used without a
   required library.
Add password type.
Add an ImproperlyConfigured exception.

 - To be used to signal when a type is being used without a
   required library.
Expose the Password wrapper.
Remove explicit dependencies.
Have travis install passlib.
Merge pull request #25 from kvesteri/topics/optional

Remove explicit dependencies.
Added tests for TSVector autoloading
Merge remote-tracking branch 'origin/master' into topics/password

Conflicts:
	.travis.yml
	setup.py
Rename .raw to .hash
Initial UUID type implementation.
Add documentation blurb for UUIDType.
Merge remote-tracking branch 'upstream/topics/uuid'