Fixes for asset pipeline.

Remove rake namespace - clashes with rake variable used in precompiling
assets. Make sure the symlinking and theme installation are done before
precompiling assets.
Handle a request with no user in the show request function
Set blog and twitter params to empty string

This is the default value from lib/configuration.rb if they aren't set
and null values cause errors when .empty? is called on them.
Upgrade to latest version of Rails
Merge branch 'hotfix/0.16.0.7' into wdtk