Remove SSL requirement from Gemfile source

Looks like rubygems.org is still having SSL issues. We'll switch back
to SSL in the future, if need be.
Add rdoc dependency to Gemfile

Needed for rdoc tasks in Rakefile
Use 1.8 hash syntax
Remove unused constants

1.8 specs won't pass with these declared - and I think this is debt
from days gone by.
Encode response_body fixture if possible
Encode response correctly on 1.8

Changes #6 to use encode!
Ensure we properly encode the response body fixture in our specs as well
Range selector on 1.8 returns integer

Ensure last character returned in range selector is an
actual character and not it's numeric value.