Update .travis.yml

pegging version of bootstrap.py
removing changes
setup tools upgrade after activate
Merge pull request #483 from ENCODE-DCC/travis_fix

Travis fix
Upgraded setuptools default version
Merge pull request #484 from ENCODE-DCC/setuptools_fix

Upgraded setuptools default version
Merge remote-tracking branch 'origin/master' into 1718_aggregations
Fixed few more issues with aggs