Bug 935776: fix bootstrapping on Mac Mavericks

* don't prompt for gcc-4.6 and MacSDK10.6 on Mavericks
* prompt for gnu-tar if no compatible archiver is found
Bug 982463 - Add dolphin support to B2G. r=mwu
bug 965803 -- add repo init and sync flags
Bug 994985 - All Tarako builds are userdebug, not user or eng. r=mwu
Bug 1004342 - Fix get_about_memory.py crash when printing timeout error message.

The operator for combining sets is `|`, not `+`.
Bug 1004331 - Handle unexpected excess files in get_about_memory.py
Bug 988277 - Update repo frontend to 1.21. r=mwu
Bug 1007566 - Assert that the /system partition is rw mounted r=gsvelto
Bug 1008094 - Add device and gonk version checks to FOTA r=gsvelto
Bug 997029 - Don't build Gaia when ./flash.sh gaia
Bug 997029 - (follow-up) Default to /system/b2g
Bug 1009753 - Check for TARGET_DEVICE r=gsvelto
Fix path to sp7715ga profiling manifest
Add optional modified kernel configs if needed to enable profiling
Support toolchain path used in jld's profiling manifests
Collect all profiling modifications in folder profiling
Add patches required to build for profiling
Add patches for Spreadtrum to improve performance
Simplify profiling manifest check in config for flame