refactor: fix Rake link and fix missing HTTPS on links

Makefile

-# mruby is using Rake (http://rake.rubyforge.org) as a build tool.
+# mruby is using Rake (https://ruby.github.io/rake/) as a build tool.
 
 RAKE = rake
 

build_config/ArduinoDue.rb

 # Cross Compiling configuration for Arduino Due
-# http://arduino.cc/en/Main/ArduinoBoardDue
+# https://arduino.cc/en/Main/ArduinoBoardDue
 #
 # Requires Arduino IDE >= 1.5
 MRuby::CrossBuild.new("ArduinoDue") do |conf|

build_config/chipKITMax32.rb

 # Cross Compiling configuration for Digilent chipKIT Max32
-# http://www.digilentinc.com/Products/Detail.cfm?Prod=CHIPKIT-MAX32
+# https://www.digilentinc.com/Products/Detail.cfm?Prod=CHIPKIT-MAX32
 #
 # Requires MPIDE (https://github.com/chipKIT32/chipKIT32-MAX)
 #