Build web apps with patch files
Apply patch scenario:
1. Check whether it's a git submodule, otherwise, skip below scenario
2. Get sorted patch file list
3. Check whether patch file under WebApp folder, if no, skip below scenario
4. Checkout the submodule to 'master' branch
5. Remove 'auto_patch' branch which was created during previous build
6. Create a new 'auto_patch' branch
7. Apply all the patches
8. Checkout to 'master' branch

'auto_patch' branch will be remained after build for further review.

BUG=#16