Merge pull request #62 from palf/master

Fixes #59
Bump version pending bug fix release
Remove unnecessary GHC options
Fallback to cairo/pango 0.12 due to 0.13 having build issues with the stable GHC
Preserve the engine state after each render. Fixes #63
Cleanup based on HLint suggestions
Bump version to 0.6.2 for another optimization-focused patch