Can't add additional JS libraries to Javascript runtime running kernel code

**This commit changes the structure of manifest.yaml and may not be backward compatible for existing apps**
*It requires some discussion as to how migrations for existing apps need to be supported since I have not seen an automated way to upgrade calatrava in existing apps*
Some details [here](https://groups.google.com/forum/#!topic/calatrava-mobile/8RlO6W8qF1c) as well.

**Commit Details**
Adding the ability to specify js libraries that need to be loaded with js runtime running kernel code. This change alters the structure of mainfest.yml for all three projects by adding features and kernel_libs as two distinct sections. Any files added in kernel_libs will be added to load_file.txt for all platforms and will be loaded while initializing the js runtime for kernel code.