Use load-extension in Makefile instead of \i

the \i command is removed from orafunc.sql and the --load-extension
option is added in Makefile.
Add mising regression tests
Merge pull request #5 from okbob/master

remove unused variable
Merge pull request #7 from okbob/master

don't need a special SQL script files for 9.1 and higher
Merge pull request #6 from b-emerson/master

Add Missing Regression Tests