Remove call to gcc for calculating type sizes

This method supported calculating type sizes for types outside of the
Camkes built-in range but isn't used and uses incorrect compiler
arguments.

templates: clean up testmacros

The exclusion set for testmacros is no longer a limited hack, but now
a more general hack covering more use cases. We move this set to
macros.py to be more self-documenting, and update its entries.

templates: Ignore ROUND_DOWN macro in macro test

Added the ROUND_DOWN macro to the exceptions list in the macros
test. This avoids it from being flagged as an unused macro.

templates: exclude new macro from unused_macros

maybe_set_property_from_configuration is used by other macros and is not
unused, but the test doesn't pick this up.

tests: add basic unit test for get_perm

tests: Print out unused macros if test fails

Fix licenses

Temporary workaround for template macros that will be used by the label mapping.

Add a test for unused macros.

This commit cherry-picks 05cfffd1506e4dc28d831c2b339b3039270af6be from
ssh://github.inside.nicta.com.au/mfernandez/project.

Add a test that macros.sizeof works correctly.

This commit cherry-picks 91050ed094e61f6b79cfabd7c53aabbc1f14381d from
ssh://github.inside.nicta.com.au/mfernandez/project.