Node 0.8 was stalling travis builds. Updated travis.yml to remove Node 0.8 build environment

- Erring log: https://s3.amazonaws.com/archive.travis-ci.org/jobs/34187132/log.txt
- Also added build trigger for commit to `develop` branch.
Merge pull request #28 from fusioncharts/feature/remove-node0.8-from-ci

Node 0.8 was stalling travis builds. Updated travis.yml to remove Node 0...