Some tidying up

Adding a .ruby-version @ 1.9.3. Railsbot still needs iconv, which
has been removed in 2.0.0.

Added the summer github repo to the gemfile for sourcing the gem.

Changed the default config for summer to use postgres now this is
in the Gemfile
Improving the seen/since/whois commands

Stopping railsbot from crashing if 'nick: !since' is used. Instead
this will use 'nick' as the target of the command.
Merge pull request #28 from workmad3/patch-4

Fixing a crash and some general tidying up