AudioFlinger: Add resampler using Speex library

In addition to earlier quality settings there is a new setting, which
uses libspeexresampler from external/speex directory. The output
quality with SPEEX_QUALITY is better than with HIGH_QUALITY
setting due to a proper anti-aliasing filter.
Cherry-pick from ICS.

Change-Id: I64aef1fbf3f0802d9f1948328b9864c603c878a0
Signed-off-by: Daniel Levin <dendy@ti.com>

[Ported to JB MR2 and squashed with the following changes]

[Daniel Levin <dendy@ti.com>]
    AudioFlinger: Move sample-rate conversion check to resampler class
    AudioFlinger: AudioResamplerSpeex: Do not overwrite output buffer
    AudioFlinger: Prevent invalid free()'s in Speex resampler

MW: Port to Lollipop, add OMAP_TUNA support.