unix Makefile: Split off optimization options to COPT variable.

To allow easily try different optimization and configuration options
without patching any files.

Some tools do not support local/static symbols (one example is GNU ld map file).
Exposing all functions will allow to do detailed size comparisons, etc.

Also, added bunch of statics where they were missing, and replaced few identity
functions with global mp_identity().

For some reason, STM port, while it's 32 bit, needs %lu and %ld for
printing machine_uint_t and machine_int_t.

Enable GC for Unix port

Enable link map file generation.

Bah - Removed a couple of warnings for teensy that I didn't notice before.

Note: none of these functions are used by STM port, so they're provided
to have parity with pre gc refactor status quo, and in case they will be
needed in the future by some extension writers.

With range(10000), doesn't fit into 128K heap.

Please don't submit patches with tab indentation!

Test function needs to be called by something else. Test heap size reduced so
its dump fits on a screenful of a typical terminal.

With a nice traceback, helps debugging much better.

Addresses issue #275.

Addresses issues #272 and #273.

Updated teensy to work with latest on master

Get rid of calloc().

Clean up handling of function return type annotation.

Added analogRead, analogWriteXxx and servo support for teensy.

If there's malloc and memset, then there's no need for calloc, especially if
we need to implement it ourselves.