more attempts to clean up the code to work better on NFS : seems ok now, but expect more "bug" fixes to come (and more cleanup as the code is a bit hacky)

add automatic cacheing of various functions, and a cache_test() routine to test the runtimes with and without caching

beware though: there are many debugging options still built in, and the gridcode should (but doesn't) have a unique filename

changed quit() to quit(1) with a more complete error message to handle the (common) case when the BINARY_C environment variable is not set. With quit(), the return code is 0 so pip just gives a confusing "oserror". With quit(1), an error is raised and the output sent to the terminal.

implemented binary_grid-style statistics over last n_logging_stats verbose outputs (50 by default)

added ANSI colour to output if in a terminal (i.e. with a tty)

fixed the cmd-line parser to work in the form x=y as intended (downside: no help output, but that just said how to use the old parser which doesn't exist now)