Corrected "switch" disassembly

Old output:

switch 0f3042ea
casetbl
40ff078d 2
a6b2b9e3 2

New output:

switch 00000304
casetbl 2 00050e00
case 2 00004034
case 3 0001f0bb
More forgiving disassembly.
disasm: Split DisasmDump() into smaller functions
disasm: Don't hide actual numeric operand in CALL/SYSREQ instructions

The real function address or index is sometimes useful. Just show
function names in comments, like "call 01010101 ; my_public".
Remove support for JREL

JREL doesn't work with JIT, and nobody uses it anyway. Plus it's
obsolete in newer versions of AMX.
Merge branch 'master' into opcode-v2

Conflicts:
	opcode.inc