Replaced zaxisDefLtype()/zaxisInqLtype() by cdiDefKeyInt()/cdiInqKeyInt() with CDI_KEY_TYPEOFFIRSTFIXEDSURFACE.

Removed obsolete CDI grid functions gridXXXXpole(), gridXXXYpole(), gridXXXAngle() and gridIsRotated().

* This reverts r3646 and r3645.
* xrealloc/xmalloc are there for a reason:
** Every call to these functions does not check the return value of
   the memory allocation, hence error checking must be performed
   in the wrapper.
** This was historically done in the macros defined in dmemory.h,
   but redefining any identifier from the standard library to
   something which behaves differently is confusing.

* Also change zaxisCompareP to return 1 on differences.

* Also compare uuid in grid comparison.

* Also extend corresponding resource copy test.

* This is part of the bits needed to facilitate multiple/incremental
  resource updates on I/O servers.

* Also add code to test for it with valgrind.

* Also declare functions not directly called static.

* Also include namespaceNew and namespaceDelete in cdi.h.

* This should complete the separation of serial and parallel parts
  of the library.

* This also adds separate documentation, header, Fortran wrappers and
  pkg-config file for the cdi-pio part of the library

* Said generic can be replaced with an MPI-specific version, thus
  cleanly separating serialization of meta-data itself and MPI-
  communication.

* This results in an API change for CDI-pio initialization. Users are no longer
  required to specify the number of namespaces in advance.