cload: command for loading COBOL modules

Only "kind of a patch" this time as I've not checked yet how to do the necessary string handling.

The issue behind this is that different COBOL debuggers allow you to "load" a module that is not-yet-called to set breakpoints or search the source.

Since GC 2.2 this can be mimic'd by invoking

call (size_t)cache_preload ("/path/to/SOME.so") (returns non-zero if module specified with full-path is now available)

and it would be nice to be able to do something like

cload /path/to/SOME.so ("similar" to GDBs load command)

note: GC 3.2 will additionally ship with a function that can be called as

call (size_t)cob_try_preload ("SOME") (returns non-zero if module specified with name (searched in COB_LIBRARY_PATH is now available; returns 2 if it already was pre-loaded before and 3 if it was previously CALLed and not CANCELed)

For everything pre 3.2 care must be taken to not pre-load a module after it was already called and not-yet canceled.