allowing multiple spaces between scope info
removing trailing spaces
adding .gitignore
removing boilerplate from test file
adding basic debug information
allowing permissions with underscore ("_")

Some Facebook permissions have underscores, such as 'user_birthday',
but those weren't being accepted by the argument validation code.
adding MYMETA to .gitignore
more tests for Dancer::Plugin::Auth::Facebook
making exported facebook() keyword all lowercase

Perl variables, as well as Dancer-exported plugins, are most
commonly written in 'snake case', that is, all lowercase and
with underscores ("_") separating words. In case of "Facebook",
it's just a single word, so the FaceBook() exported keyword should
be renamed to 'facebook()' instead. This is also compliant to the
Dancer::Plugin::Auth::Twitter interface, which exports 'twitter()'
and not "Twitter()".
minor documentation fix

from the code, the actual default scope is 'email', not 'default'.
putting all the user's facebook information under session('fb_user')

The plugin was just storing basic user data (namely: email, username
and name). Now the plugin stores all the user data returned by Facebook
under the 'fb_user' session key. This allows the developer to choose
which data to use.
access_token => fb_access_token to play nice with others

In a large web app, chances are 'access_token' is already used
as session key by either the app itself or some ill-behaved plugin.
So, in order to play nice with other plugins and avoid namespace
clash, we changed the (internal) session('access_token') key to
session('fb_access_token').
minor code and pod tidying
updating Changes file