COBIA initialization diagnostics

[jasper]

On some systems, particularly during installations, cobiaRegister (or wCobiaRegister) typically fails with the message "CAPE-OPEN initialization fails".

Several attempts to debug this after-the-fact have failed, either because the problem is not reproducible on my computer after transferring all target files, or because the problem spontaneously corrects itself.

I suggest to put in place better textual error messages about why COBIA fails - e.g. report on failure to load the COBIA core DLL (with path to the DLL and error code), report on failure to load any of the function pointers, etc.

[jasper]

In [c38371e19cac60fe1cec8e47dd86365d27a19e42]:

fix #174

[jasper]

In [44e0416f8e152c71ad480e6170cbac9908aac14d]:

fix #174

[jasper]

In [c0d66d1d093c4540949b7e8d3d64624255e5fb97]:

additional fix #174