Merge pull request #44 from prakhar1989/master

Added iterationrunner as a class and fixed some documentation.

Please add the PR's as soon you do anything else.
Adding feature for ResponseExporter, need to add where to call the exporter function from.
Rectifying problems with merge.
Adding some comments, as per PR.
Exporting the file.
Merge pull request #45 from viig99/master

Adding feature for ResponseExporter, need to add where to call the expor...
Commit for adding option to modify env variables from with test cases, UT included.
PR comments.
Merge pull request #46 from viig99/master

Commit for adding option to modify env variables from with test cases, U...
Added data test data
Fixed merge conflicts