chore(tasks/test): save coverage report to coverage folder
chore(tasks/test): generate lcov report
chore(travis): send coverage data to codeclimate
fix(travis): only use COV variable on building

Some packages use COV environment to require code. Putting COV environment
variable on global causes node-sass to fail to install.
Merge pull request #23 from bemusic/coverage#21

Integrate code coverage with codeclimate