Avoid Syntax Error on CRuby v1.8

CRuby v1.8 dose not support named capture

fix syntax highlighting

`a` in `a.m += c` or `a[b] += c` should be evaluated only once.

Add missing regs update

mrb_vm_define_class() may realloc() mrb->c->stack because it calls
mrb_funcall() for inherited hook. If mrb->c->stack is realloc()-ed, regs
refers orphan address.

deprecate and fix VS2010/2012 build

They don't have <inttypes.h>, only <stdint.h>.

Fix doesn't work bintest on :visualcpp toolchain

Added example for cross-compiling on Intel Edison

Add appveyor.yml

Reduce compiler include_paths

Add default benchmark build config