Add pginterface into main tree, called pgeasy.

contrib/README

contrib/findoidjoins/README

contrib/pginterface/Makefile

src/configure.in

src/interfaces/Makefile

src/interfaces/libpgtcl/Makefile.in

src/interfaces/libpq/Makefile.in

src/interfaces/pgeasy/Makefile.in

src/interfaces/pgeasy/README

src/interfaces/pgeasy/examples/Makefile

src/interfaces/pgeasy/examples/pginsert.c

src/interfaces/pgeasy/examples/pgnulltest.c

src/interfaces/pgeasy/examples/pgwordcount.c

src/interfaces/pgeasy/halt.c

src/interfaces/pgeasy/halt.h

src/interfaces/pgeasy/pgeasy.3

src/interfaces/pgeasy/pgeasy.c

src/interfaces/pgeasy/pgeasy.h