Added Factory for Pages

Added a factory for page generation. It uses the new "available_pages"
from the Page to figure out what it can/can't generate and then creates
them. Redid bin/dotgrid and the generator to just pass in the page types
that are needed.

Still need a) more tests and b) redo the README + "base" (still need to
rename that or something).
Redid the Factory

Redid the factory so it was more in line with the way other
factories are impmemented. Also added test cases for it.
Clone Params Before Passing

This is probably the wrong way to do this but is fine for now. Since the
pages actuall modify the params value, we need to clone it before
passing. We should probably just pass what's needed to the individual
pages.
Lined Up the Pages Hash
Clean Up with New Options

Plus added gemnasium badge to README
Fixed base to Reflect New Usage
Upgrade to Latest Prawn Gem

Added complete example to base.
Merge pull request #22 from slabounty/page_factory_20

Page factory 20