Titleize blob action buttons. [failure unrelated]

Created by: cirosantilli

As supported by dosire at: https://github.com/gitlabhq/gitlabhq/issues/7789#issuecomment-57126623

I think it looks better.

After:

Before:

In particular, those buttons being lower case already conflicts with the analogous buttons on merge request diffs.

Also titleized the history link on the tree view: it makes tests simpler, and would have to be done sooner or later. Screenshot (link on upper right):