We have now again two functions called h_platform_vasprintf and
h_platform_asprintf. On windows they are implemented in terms of vsnprint
and the like. On BSD/GNU libraries we use the supplied vasprintf and
asprintf.

The pretty printing format chosen is USER:<token name>

We use the registry function `h_get_token_type_name` which returns 0
when no name has been defined. This will print (null) as a token name.

Revert "C++ tests set up. They probably don't compile; need to write iostream ops for prettyprinting and set up C++ build in scons." Should have branched it.

This reverts commit 6a29277d.

C++ tests set up. They probably don't compile; need to write iostream ops for prettyprinting and set up C++ build in scons.

Cleaned up some memory leaks, got rid of gsequence, improved test macro to free memory that it allocated