fix NDK libdir and do not cache the NDK API version (as real api version might change in a gem)
fix NDK libdir and do not cache the NDK API version (as real api version might change in a gem)

katsuyoshi/RubyMotion,HipByte/RubyMotion,hboon/RubyMotion,katsuyoshi/RubyMotion,hboon/RubyMotion,katsuyoshi/RubyMotion,katsuyoshi/RubyMotion,hboon/RubyMotion,HipByte/RubyMotion,HipByte/RubyMotion