Change util.c and util.h to non-template files

Previously util.c and util.h appeared as both template and
non-template files in Makefile.am by accident. This change also
means that iqsutil.h can also be changed to non-template.

Only one macro in util.h, EGLPNUM_SWAP, uses the template type
system. This macro is moved to eg_numutil.h.