Merge pull request #32 from goyal1092/feature/task-4408

Refactored product images #4408
Added Coveralls #4507
Merge pull request #33 from aroraumang/feature/task-4507

Added Coveralls #4507
Default image function field in product
Merge pull request #34 from prakashpp/develop

Default image function field in product
Added nereid-image transformation as dependency #4408

Review Id: 12823001