Rationale: "Basic allocation" refers to things outside of parsing proper,
mostly initialization. If such allocations fail, the system is globally
emory-starved from which it will likely not recover by returning failure.
In this case, terminating the process is in fact the most robust strategy as
it may mean the difference between a permanent hang and a temporary crash.

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