manifest: add a general github remote

Just makes it a bit easier to track personal repos and those from themuppets, etc
in local_manifests.

Change-Id: I05105b94288e922470c3c57d442867600ba10fe3
default: Fork android_system_extras

Change-Id: I532c0adca3e35a37b8e6cfc2fe9c4d2701b37962
Merge "default: Fork android_system_extras" into android-4.3
manifest: switch to vendor/omni

Change-Id: I32d7171459351ae19e2f5e55f5f66eece9e9b935
default: Use our own broadcom_libbt

Change-Id: I77e1900b0397e957e1b0dda5f0ca2fcd9533a35c
Merge "manifest: switch to vendor/omni" into android-4.3
Fix merge

Change-Id: Id6c05342fabfb4d8055c561c8f22322ca4c4b756
Shift to omni system/core

Change-Id: I67427f8b7d619885eb3c4f819e0deea09ce75a86