64 bit arithmetic soft fork

If anyone is interested to see how this set of proposals could be used by other op codes please see my new post about OP_INOUT_AMOUNT

Here is a direct link to a few test scripts in the python test framework

https://github.com/Christewart/bitcoin/commit/c617c5c3b0d21499b196184b5279b45627060cb5#diff-2e2556d1d2e3a75b547bbb86bd68567f275ba6d17b9bf4541facef9f2b1cfb30R124