Add very basic keyring support.

Requires keyring: https://pypi.python.org/pypi/keyring

To set the password, run:

    keyring set pycarddav:$account $username
Merge pull request #77 from Stebalien/develop

Basic keyring support

Requires keyring: https://pypi.python.org/pypi/keyring
To set the password, run:
    keyring set pycarddav:$account $username
README update on keyring
updated version to 0.5.2 (dev)
README: some words on conflict resolution
catch 'broken' vcards

broken in a sense that vobject cannot parse them
these cards won't get inserted into the db, but instead a warning is
printed and, in debug mode, the whole vcard is printed.

this should 'take care' of cases like gh #78 for now
ensure we don't create duplicate records on merge

https://github.com/geier/pycarddav/issues/74
incremented db version

previous commit makes this necessary
adding Jamie McClelland to CONTRIBUTORS

patch apply failed, turns out I'm not proficient enough in git to
resolve this -> manually 'patch'
don't insert duplicate accounts

https://github.com/geier/pycarddav/issues/75
pep8ing and typos
fixed config dump

raised exception before with pc_query
better type checking
fixed default db path
fixed argparse DeprecationWarning

this should fix github #82
thanks to brianpcurran for reporting this bug
manpages

for pc_query, pycardsyncer and pycard-import
release v0.6
Merge branch 'develop'