now working on 0.3.0
[skip ci]
removed reg.Magic as it was no longer needed, moved ASCII_BLOCK to the only method that uses it
new autodoc options
updated unit tests
turned FileLoader into an abstract base class
replaced PGPBlock with new abstract base class PGPObject
updated PGPSignature enough to load existing signatures using the new ABC scheme
moved PGPKey to keys, for now
removed PGPBlock
commented out pgpload for now
copied PGPKey from pgp to keys; stubbed out some of its API changes
updated Packet to use the new PGPObject ABC
updated Signature to work with Packet and the new PGPObject ABC
new util functions
saving current state
Merge branch 'hotfix/0.2.1' into develop

Conflicts:
	pgpy/_author.py
moved keyfields up into packet as there's not really enough here to justify one package
setup.py update for fields getting reorged
temporarily commented out everything as not all of the contents will be needed, and none of it is currently being used
moved CWD_As decorator into conftest; it's not being used yet, though
renamed current test files (and deleted the empty one) so they aren't executed, as they won't work anymore as-is and need to be (mostly) rewritten from scratch
beginnings of the new test suite - #82
benchmarking script; living here temporarily, should be moved later.
some new and/or reorganized test material
implemented new object model - #80