HKG15-408: ARM v8-A NEON optimization

ARM v8-A NEON optimization, with the following outline – Zhongwei/Phil Wang With FFT optimization as an example, following topics are discussed. a) Performance boost using ARM v8-A NEON b) NEON-optimization workflow for Ne10 c) Some tips with example of Ne10 FFT and Android libraries d) Performance comparison between assembly and intrinsic