Addied extra check for ignored build errors

In some cases aosp build fails but top level-make still will not return an
error code. This is an error in the aosp-build system, but this patch is a
work-around to help cope with this.

Category: development
Adding extra samples

Addin the ability to see GPU-freq and ext-bus freq. This is somewhat too
vendor-specific. Will revert this and make a more generic solution ASAP where
extra sample can be defined much more flexably. This however pushes the limit
of what is doable in a sampler based on a script (either internally or
externally run) as sh-loops and logic are quite slow, which will affect
temporal accuracy of the sampler.

Catehegory: development