Added MIT license to the gemspec

So that it shows up on rubygems.org
Merge pull request #351 from parndt/patch-1

Added MIT license to the gemspec
bump to rails 2.3.15
move to rails 3 dependencies
update spec_helper for dummy app
remove rails 2 config files
bump rspec and rspec-rails
bump major version
initializer no longer used in Rails 3
update Rakefile for testing with dummy app
update docs and warn about breaking changes
remove custom tasks for now
create version file, require engine from lib/radiant.rb
remove haml initializer
drop 1.8.7
adding Radiant.config method
ignore test log files
Remove deprecated `set_table_name'
Move vendorized plugins to gemspec

Rails 4.0 no longer supports these plugins
Update Gemfile.lock