Bump version number to 0.10.0.rc1
Dropped the rc1 from the version
Add contribution guidelines to README
Upgrade debugger for Ruby 2.1
Update all non-pinned dependencies
Relax version check on Rack
Relax version dependencies on Haml and Sass

This effectively upgrades us to Haml 4.
Run tests on Travis CI on Ruby 2.1.1
Update rspec to version 2.14.x
Bump year in copyright statement
Tidying CHANGES prior to release of 0.10.0
Removed unused optional argument to #path_to
Automate release testing on multiple Rubies
Don't include Nesta version in new Gemfiles
Fix test
Allow list items to be styled as such
Remove the (deprecated) cache helper
Allow Haml pages to use the textile markdown filter
Remove debugger from the bundle

Ruby 1.9 and 2.x now need different debuggers, and the tests fail on the
CI server if we hard code a particular debugger.
Return the first assigned category as parent for top-level page

Remove code to sort a page's categories alphabetically