Fix typo in Coffeescript documentation.
Documentation fix for preserve
Merge branch 'master' of https://github.com/Pringley/haml
Merge branch 'https_rubygems' of https://github.com/teeparham/haml
remove ruby 1.8 support from tests
remove support for ruby < 1.9.2
specify required ruby version >= 1.9.2
remove 1.8.7 from travis, add 1.9.2
update comments and README for 1.9.+
remove unnecessary comments [ci skip]