Some tidy-ups, version bumps, removal of #!/usr/bin/env ruby headings that don't need to be there.
Removes redundant Ruby version check.
Removes extraneous "#!/usr/bin/env ruby" headers; none of these files…
… are being executed directly.
Switches to https://rubygems.org to avoid rubygems whinging.
Bumps mentioned Ubuntu version.
Bumps recommended Ruby version to latest 1.9.3
Moves .rbenv-version to universal .ruby-version file instead.
@damncabbage nice work! Thanks for the PR.
FYI, the version of Ruby was locked to 1.9.3-p290 because it's one of the mandated versions within @bulletproofnetworks. We can probably even bump it to Ruby 2.1.0 now though.