update README & HACK with SystemZ information

HACK.TXT

@@ -7,6 +7,8 @@ Capstone source is organized as followings.
 │   ├── ARM         <- ARM engine
 │   ├── Mips        <- Mips engine
 │   ├── PowerPC     <- PowerPC engine
+│   ├── Sparc       <- Sparc engine
+│   ├── SystemZ     <- SystemZ engine
 │   └── X86         <- X86 engine
 ├── bindings        <- all bindings are under this dir
 │   ├── java        <- Java bindings + test code

README

@@ -4,8 +4,8 @@ disasm engine for binary analysis and reversing in the security community.
 Created by Nguyen Anh Quynh, then developed and maintained by a small community,
 Capstone offers some unparalleled features:
 
-- Support multiple hardware architectures: ARM, ARM64 (ARMv8), Mips, PPC, Sparc
-  and X86.
+- Support multiple hardware architectures: ARM, ARM64 (ARMv8), Mips, PPC, Sparc,
+  SystemZ and X86.
 
 - Having clean/simple/lightweight/intuitive architecture-neutral API.