Enable NEON optimized image rotate for ARM v7-A

  NEON opimized image rotate was disabled by accident. This patch
  enables it again. Fix issue #115.

Change-Id: I4aa977de8534557d98a707cc9504aac94805d571

NE10/FFT/complex-non-power-of-2 NEON

    ARM 64-bit (Cortex-A57)
    complex forward float LLVM 3.5
             Time in ms      |
        |kiss|opus|pffft|NE10|
        |   C|   C| NEON|NEON|
      60| 129| 113|   NA|  44|
     120| 148| 127|   NA|  49|
     240| 151| 128|   55|  47|
     480| 169| 142|   60|  55|
     960| 183| 149|   65|  58|
    1920| 193| 167|   71|  66|
    3840| 217| 175|   76|  71|
    SNR > 100dB

    ARM 64-bit (Cortex-A53)
    complex forward float LLVM 3.5
             Time in ms      |
        |kiss|opus|pffft|NE10|
        |   C|   C| NEON|NEON|
      60| 295| 311|   NA|  72|
     120| 368| 375|   NA|  79|
     240| 345| 342|  104|  77|
     480| 415| 407|  115|  87|
     960| 406| 378|  121|  95|
    1920| 476| 441|  138| 113|
    3840| 497| 424|  161| 126|
    SNR > 100dB

    ARM 32-bit (Cortex-A9)
    complex forward float LLVM 3.5
             Time in ms      |
        |kiss|opus|pffft|NE10|
        |   C|   C| NEON|NEON|
      60| 224| 211|   NA|  98|
     120| 265| 245|   NA| 104|
     240| 262| 240|  130| 106|
     480| 302| 274|  150| 122|
     960| 305| 271|  162| 153|
    1920| 369| 356|  230| 206|
    3840| 415| 440|  282| 239|
    SNR > 100dB

Change-Id: If9418041b01eed49dbdc8d6a18dd03f2c5684da8

make sure the fft buffer 64-bit alignment to avoid bus error

add temp buffer allocation and scaling by 2 for rfft, fix bug in fir

add float/int32/int16 FFT

optimize int32/int16 fft

optimize float fft

This release is suitable for Linux, Andriod and iOS