Revert "Rely on SDK manager plugin instead of Travis"

This reverts commit 7e3fdf65672e96633a4c45abf684bada8e317adb.
Revert "Hopefully final modification for SDK 21"

This reverts commit 4ecc9dd1fb1e067aa0eefb45d7d47d7b4e740aa8.
Revert "More modifications for SDK 21 build"

This reverts commit 61dc8fec9dccf7da4a25efb2a6b1ed8819f271cc.
Revert "Get everything set for API 21"

This reverts commit d94b8b45c720c19401bedd3051496752d8ac7736.
Revert back to SDK 20, but use plugin 14.0
Allows Android Studio (needs plugin 14) and Travis (20) to hopefully play nice