first try in adding coverty scan analysis on travis ci

https://scan.coverity.com/travis_ci
travis: fix .travis.yml syntax
travis: another shot at indenting this thing right
travis: fix typos, fix env data structure
added coverity badge
added notification email for coverity
travis: setting TRAVIS_REPO_SLUG to php-poppler-pdf

since that's how the project is called on coverity, and
coverity doesn't seem to respect it's own project:name setting
travis: make distclean before coverity_scan
Merge pull request #4 from easybiblabs/coverity_scan

Coverity scan