Improve logging

Use Python native logging feature and termcolor (if available) to
print colored output.
snapshot: Fix typo
Remove leftovers

Cleanup, no functional change.
buildsystems: Add writing permission to the executable before stripping

Stripping might fail if the executable is read-only, so we save its
permissions, add the writing bits, strip and then restore the original
permissions.
logger: Turn action messages blue

Change action messages color.