Bring back NDK toolchain because of performance issues

[TBSniller]

Fixes very slow performance on all TVs.
Kind of addresses this issue: #94. But we should not close it yet, because renicing process might be still useful.
Tested on TVs down to webOS 3.4

[smx-smx]

As per @throwaway96 analysis, you should explicitly add -mfpu=neon to CFLAGS and/or -DLIBYUV_NEON (which is correctly handled only in the gyp build).

buildroot-nc4 doesn't do that by default because it targets a generic CPU by default (-mcpu and -mtune are not set). Therefore, setting either -mcpu/-mtune is also a viable alternative.

[TBSniller]

As per @throwaway96 analysis, you should explicitly add -mfpu=neon to CFLAGS and/or -DLIBYUV_NEON (which is correctly handled only in the gyp build).

buildroot-nc4 doesn't do that by default because it targets a generic CPU by default (-mcpu and -mtune are not set). Therefore, setting either -mcpu/-mtune is also a viable alternative.

@smx-smx @throwaway96 thanks for analysis and letting me know! will test it out