clang-dev_libcxx_unity_xtra warnings for Arx in branch 1.2.1

• -Wnan-infinity-disabled [docs] (4)
• -Wimplicit-int-conversion [docs] (74)
• -Wshorten-64-to-32 [docs] (145)
• -Wold-style-cast [docs] (151)
• -Wimplicit-int-float-conversion [docs] (233)
• -Wpadded [docs] (288)
• -Wsign-conversion [docs] (833)