fixed a bug in push back list; close #1298
Merge branch 'master' of github.com:mruby/mruby
Fix crash on load *mrb
Merge pull request #1303 from kyab/sirep_fix2

Fix crash on load *mrb
add mrb_malloc_simple() that returns NULL on error
use mrb_malloc_simple() to allocate crc buffer; close #1302
Add arena save/restore around use of hash KEY.
Refactor mrb_hash_has_keyWithKey() func in hash.c
Merge pull request #1307 from carsonmcdonald/keyduparenafix

Add arena save/restore around use of hash KEY.
Merge pull request #1308 from suzukaze/refactor-hash-c

Refactor mrb_hash_has_keyWithKey() func in hash.c
Avoid read_escape() in case of regexp
Visual Studio 2013 support + strtof + inline

- VC12 has better C99 library support due to C++11
- defined strtof for VC11 or older
- define "inline" only if the C compiler is used
Fix include path of ArduinoDue example
include inttypes.h if _MSC_VER is not defined
fix unnecessary exception in mrb_get_args with "z" format.
Refactor mrb_hash_empty_p() func in hash.c
add nil.to_a, nil.to_f, nil.to_i methods
replaced POSIX header with standard C header
refactor mrb_realloc()

remove the redundant codes with mrb_malloc_simple()
Merge pull request #1310 from iij/pr-fix-regexp-escape

Avoid read_escape() in case of regexp