BR-78
cc: jesse, steven.ginn

- changed the way we build the version number
- removed duplicate version deceleration
- added a non-init api module
- freeze requirements (we were using a beta version of lxml)
NS-142 - implement css specificity in premailer

also made some work to simplify and put more structure in the code
cc: steven.ginn
fix grouping regex to allow whitespace between group name and declaration
fix override with same specificity
add test for selector grouping
create a test from the script main code
Merge branch 'release/1.12-LL'