beta 0.2.0.0

beta 0.2.0.0

• replace FreeImage with stb_image
• warn unicode error in Windows compiling
• separate clang/gcc build script for android
• add default values in fbs
• optimize CPU conv / conv depthwise / deconv / deconv depthwise / lstm / sigmoid
• add sub support in eltwise
• add reciprocal / log1p / log in unary
• add zero like / select / set diff 1d
• add batch support for permute
• add training codes
• fix metal error in dynamic separate storage type handling