Return whole key.
Refactor.

Put everything into a class, urlencode key id,
wrap example usage into __name__==__main__,
support arbitrary keyservers, don't strip hex '0x' prefix.
Support long integers for key_id.

Key-ids are really integers so support
receiving long integers as an argument to find()
Merge pull request #2 from ewindisch/eric-refactor

Refactor. Read commit messages for details.