Merge pull request #2628 from fenrir-naru/cygwin_host

Under cygwin host, ncurses.a is only available instead of termcap.a.
Fix misaligned access when reading irep; close #2630

Add padding bytes before iseq block that may be used as mrb_code[].
Note that dumped mrb format has changed.

Based on a patch from kimu_shu <alfvegardrisc@gmail.com>
specify alignment specifier for GCC and MSC; ref #2630
read whole mrb file at once to calculate correct padding offset; ref #2630
avoid using rewind(3) to load mrb files
update teeny of MRUBY_VERSION; ref #2629
%zu format is not supported by MSVC
Modify Arduino build config for IDE >= 1.5.7

Arduino IDE >= 1.5.7 Changed ARDUINO_PATH from `Contents/Resources/Java` to `Contents/Java`, mentioned in #2632
change BIN_PATH for new gc in Arduino IDE >= 1.5.7
Merge pull request #2631 from mimaki/sizeof_format_not_supported

%zu format is not supported by MSVC
Merge pull request #2633 from southwolf/patch-1

Modify Arduino build config for IDE >= 1.5.7
Merge branch 'master' of github.com:mruby/mruby
Fix mrb_iv_check function decleration
Merge pull request #2634 from xxuejie/fix-mrb-iv-check-prototype

Fix mrb_iv_check function decleration
Merge branch 'master' of github.com:mruby/mruby
add Float::{INFINITY,NAN} if available
Merge branch 'master' into c674x