x64Emitter: fix silent failure if WriteNormalOp is passed two memory operands

Should now fail loudly and clearly instead.
JIT: support immediate stores
Merge pull request #1089 from FioraAeterna/fixemittersilentfail

x64Emitter: fix silent failure if WriteNormalOp is passed two memory operands
GekkoDisassembler: fix/improve disassembly for a few instructions
Merge pull request #1091 from FioraAeterna/fixdisasm

GekkoDisassembler: fix/improve disassembly for a few instructions
Merge pull request #805 from FioraAeterna/storerefactor

JIT: support immediate stores
Fix missing "return"
Merge pull request #1092 from comex/that-aint-ruby

Fix missing "return"