Bug 868263 - Back out apitrace due to build failure

Change-Id: Idd147dcdb047c40455f6f23e4aeebf7a815740ee
Added b2g specific valgrind and vex repos
Bug 854517 - Add b2g specific valgrind and vex repos (for manifests missed in last push)
Reverting valgrind/vex commits (Bug 854517 e16fe0ebb94ef527bea4876b4ef994fb4c577d8a e819e3792dfe2b2f434261b2e47e2279830de45f) due to emulator bustage
Reverting manifest revert now that valgrind repos are fixed.

Revert "Reverting valgrind/vex commits (Bug 854517 e16fe0ebb94ef527bea4876b4ef994fb4c577d8a e819e3792dfe2b2f434261b2e47e2279830de45f) due to emulator bustage"

This reverts commit 0931407d1b2689fb8d08ba25683ab558bf47d920.
And reverted again, because vex symlink checkout doesn't work on any other box

Revert "Reverting manifest revert now that valgrind repos are fixed."

This reverts commit 09429853a96a23b8c7f8c8fee74b4500a34d2e49.
Bug 854517: Add external/valgrind and external/VEX to manifests
Add nexus 4 manifest
Bug 831147 - Integrate apitrace into build

Add apitrace repo to manifest files, so that it gets fetched
when the top-level ./config.sh script is run.
Merge pull request #77 from vasild/apitrace

Bug 831147 - Integrate apitrace into build
Bug 852583: switch emulator system/core and qemu-kernel to B2G github.

Change-Id: Ibc1989882c27f1fb790474e65ebb7333c93186ec
Merge pull request #66 from vicamo/bugzilla/852583/bluetooth-emulation

Bug 852583: switch emulator system/core and qemu-kernel to B2G github. r=mwu, f=jgriffin
backout bug 852583 because git.m.o syncing system does not handle new repositories
backout bug 831147 because git.m.o syncing system does not handle new repositories
bug 831147 - reland 91da030 now that repository is mirrored p=vd r=mwu
Merge pull request #66 from vicamo/bugzilla/852583/bluetooth-emulation

Bug 852583: switch emulator system/core and qemu-kernel to B2G github. r=mwu, f=jgriffin(cherry picked from commit abcffdac12c1c2c79e13f76405c47887308b3942)
Merge remote-tracking branch 'upstream/master'