fix opcode for JML Absolute indirect long
add jml($1234) for JML Absolute indirect long
Merge pull request #83 from AntiheroSoftware/ca65-65816

Fix for pull request #80 bad JML opcode and adding syntax for Absolute Indirect Long
Have _heapmaxavail() work as advertised.

The cc65 doc explicitly states that the return value of _heapmaxavail() can be used as parameter of malloc(). To actually allow for that the size of HEAP_ADMIN_SPACE has to be substracted from the raw size of the largest free heap block.
Merge remote-tracking branch 'upstream/master'