Updated Url.js to support local images

[mainak30121994]

Added support for local image files

[DongyuZhao]

1. Please modify the code in src and run gulp, it will generate the code in dist. Any direct modification in dist could lost since gulp will delete this folder before it build and copy new files into it.
   2.Please merge this PR to release_1.x branch as that branch is what we are currently using in production. master branch is a working branch for latest schema.

[DongyuZhao]

Do not modify the file in dist directly. Dist folder is the output folder of the compilation from src and any direct modification will lost once we run build. Please modify files in src and run gulp to make this change.

[DongyuZhao]

Please move the new test rule into a separate function for semantic comprehension.

[DongyuZhao]

Please do the modification based on release_1.x branch and merge it back to release_1.x since it is currently the production branch. Master branch is a working branch and wont go alive in product in a certain period of time.

[DongyuZhao]

#11