move SQL-exposed functions out of libpgcommon

[bnordgren]

In general, it seems that anything having a need to be directly accessible to SQL should not be in libpgcommon, but rather in postgis or raster. Putting it in libpgcommon seems to be causing an issue for Windows.

Attached patch cleans out libpgcommon. Apply against r7757

[strk]

In file included from /usr/include/postgresql/8.4/server/postgres.h:47,
                 from ../libpgcommon/lwgeom_transform.h:13,
                 from lwgeom_transform.c:14:
/usr/include/postgresql/8.4/server/c.h:235: error: redefinition of typedef ‘int32’
../liblwgeom/liblwgeom.h:147: note: previous declaration of ‘int32’ was here
/usr/include/postgresql/8.4/server/c.h:247: error: redefinition of typedef ‘uint32’
../liblwgeom/liblwgeom.h:146: note: previous declaration of ‘uint32’ was here
make[1]: *** [lwgeom_transform.o] Error 1
make[1]: Leaving directory `/home/src/postgis/postgis/postgis'
make: *** [all] Error 1

[strk]

I had to swap includes in lwgeom_transform.h. Committed in r7758