Fix: #231. Support xsd:int and xsd:long.

[ioggstream]

This PR

• treats xsd:int and xsd:long as xsd:integer

[davidlehn]

See my comments in #231.

• I think this would at a minimum need to be optional so strict spec behavior is possible.
• I see the test suites pass, but that may be lack of coverage of this specific situation?
• Looks like the tests are doing some checks at value bounds. But I think it would convert values outside that anyway? Sort of an open question if this should be garbage-in-garbage-out processing, or if strict bounds checks are needed in cases like this.
  • (I have thoughts for more general "well formed" modes to trade of validity checking vs performance. That might work here too.)