Implement more thread-safe API/fix typos
Make fcgx_init_request reenterant

multi.m:
    fcgx_init_request used static storage, which is not reenterant or thread
    safe.  Allocate this structure on the heap.
Create a "request" type for requests rather than using c_pointer.

It is more typesafe to use a Mercury data type for each foreign type, it
prevents any user from mixing up different c pointer.  I've also returned
the request inside a maybe() when it is created by fcgx_init_request which
is more idomatic and also helps with safety.

This change has also allowed me to remove the type casts in the C code as
that's handled automatically by Mercury's FFI.

multi.m:
    As above.
add get_param_r variant (remember to clean this up with nice abstractions)
Formatting/readability
Add templates for threadtest, brick-laying
ditto
Mercury.options update
Add "tags" and "clean" Makefile targets

Makefile:
    As above.

.gitignore:
    Add a .gitignore file.
Use the request type for fcgx_get_param_r

multi.m:
    As above.
Improve mfcgi_threadtest

mfcgi_threadtest.m:
    Added error checking.

Makefile:
    Build mfcgi_threadtest in a parallel grade.