Merge pull request #25 from tomwys/master

Support for second error format
Merge pull request #27 from tomwys/master

Exceptions categories
Move FacebookError and HttpError under GraphAPI namespace
Rename HttpError to HTTPError

> When using abbreviations in CapWords, capitalize all the letters of
> the abbreviation. Thus HTTPServerError is better than HttpServerError.

- PEP 8 -- Style Guide for Python <http://www.python.org/dev/peps/pep-0008/>
Don't raise HTTPError upon receiving "false" from Facebook
Convert any exception raised by requests to HTTPError
Only convert RequestExceptions to HTTPErrors
Add mock to DEPENDENCIES
Nitpicking
Fix a bug that prevented documentation from building
Document test dependencies

Fixes #26
Rename DEPENDENCIES to requirements.txt

Fixes #29
Update installation instructions for Travis CI
Update installation instructions
Fix typo
batch api response can be empty
Ah, of course, can't perform 'in' on None
Merge pull request #30 from honzajavorek/batch

Batch API response can be empty
Update description
Upgrade requests