Display license info for all gems

[qrush]

RubyGems.org could also guide its users to knowing about
the licenses of every gem uploaded to it, by displaying the license name
(and a link to the license text) on the page for that gem and by permitting
the rubygems library to expose the license as gem metadata.

From this thread: http://rubyforge.org/pipermail/rubygems-developers/2011-October/006881.html

We'll already have to go through every version to get the size data in #310, could do both at the same time here.

[mreider]

+1

Within most corporations, government institutions, foundations, etc., there is an expectation that we keep our licenses in order. Rubygems could really make our lives easier by providing this kind of information.