Introduced a config file to store test parameters

1. Removed shell script to store environment variables
2. Introduced a config file to store test parameters
3. Introduced an option to store host, user in config file so the user can just run #fab <taskname>
4. Moved all test paramters to the new config file
Merge pull request #5 from sthirugn/testupdate

Introduced a config file to store test parameters