changes to process attachments as gists

Hello -- This pull request is far from something you should actually commit as-is, but I thought you might be interested in the changes in general.  I made these in order to migrate Guice from codesite to github, and wanted to try to move the attachments too.  The idea is that I did a dry run first in order to slurp down all the attachments as files locally, and then I do a real run that detects if the files are binary or text, and uploads the text ones as gists (and links directly to the gists in the github attachment).  The binary ones are linked back to codesite.