Blurb truncation; require profile name

Requiring profile name on updates, but not on creation since Profile creation happens during the github authentication process.  Once the User/Profile is in the system, blank names are no longer allowed.

I admit that the error display for the Profile editing form is not very clean or DRY. The default HTML generated by the text_field method and the Twitter bootstrap HTML structure don't mix well together.  I'm sure there's a form-related gem that would generate Bootstrap compatible HTML, but I'm pressed for time at the moment and wanted to get this pull request up, at least for feedback.

Instead of restricting the blurb length via migration and asking poor Steve to shorten his bio, I thought we could just truncate it and provide a link to a Profile#show page that displays the full text.