Adds jobs to the Travis cronbuild matrix to build ARM, AArch64, and Android packages. Adds toolchain setting based on the existing env var and parameter scheme into package.cmake to match runsuite.cmake. Adds logic to exclude the Dr. Memory build for AArch64. Adds ignoring of a "git tag" failure to handle races among the four jobs.
Issue: #2861 (closed) Fixes #3002 (closed)