Reorganization

- Separated iBasso devices from PLATFORM_ANDROID. These are now standlone
  hosted targets. Most device specific code is in the
  firmware/target/hosted/ibasso directory.
- No dependency on Android SDK, only the Android NDK is needed.
  32 bit Android NDK and Android API Level 16.
- Separate implementation for each device where feasible.

Code cleanup

- Rewrite of existing code, from simple reformat to complete reimplementation.
- New backlight interface, seperating backlight from touchscreen.
- Rewrite of device button handler, removing unneeded code and fixing memory
  leaks.
- New Debug messages interface logging to Android adb logcat (DEBUGF, panicf,
  logf).
- Rewrite of lcd device handler, removing unneeded code and fixing memory leaks.
- Rewrite of audiohw device handler/pcm interface, removing unneeded code and
  fixing memory leaks, enabling 44.1/48kHz pthreaded playback.
- Rewrite of power and powermng, proper shutdown, using batterylog results
  (see http://gerrit.rockbox.org/r/#/c/1047/).
- Rewrite of configure (Android NDK) and device specific config.
- Rewrite of the Android NDK specific Makefile.

Misc

- All plugins/games/demos activated.
- Update tinyalsa to latest from https://github.com/tinyalsa/tinyalsa.

Includes

- http://gerrit.rockbox.org/r/#/c/993/
- http://gerrit.rockbox.org/r/#/c/1010/
- http://gerrit.rockbox.org/r/#/c/1035/

Does not include http://gerrit.rockbox.org/r/#/c/1007/ due to new backlight
interface and new option for hold switch, touchscreen, physical button
interaction.

Rockbox needs the iBasso DX50/DX90 loader for startup, see
http://gerrit.rockbox.org/r/#/c/1099/

The loader expects Rockbox to be installed in /mnt/sdcard/.rockbox/. If
/mnt/sdcard/ is accessed as USB mass storage device, Rockbox will exit
gracefully and the loader will restart Rockbox on USB disconnect.

Tested on iBasso DX50.
Compiled (not tested) for iBasso DX90.
Compiled (not tested) for PLATFORM_ANDROID.

Change-Id: I5f5e22e68f5b4cf29c28e2b40b2c265f2beb7ab7

check handle before clean up buffer in flush().

Change-Id: I36a130c45c9f5dce97aa723ef98922b6935ead75

surround_enabled was never true, end up dsp_surround_flush didn't work; Thats why a cracking noise occurs in right channel when moving track positions.

redo pbe/surround flush in a much simpler way suits the current single buffer style.

Change-Id: I394054ddfb164b82c90b3dcf49df4442db87d8d2

Most of the work comes from http://gerrit.rockbox.org/r/#/c/1088/
by Thomas Jarosch.

Change-Id: Iaa673dad2388d1e44fc95ffaa14bafadc6158101

perceptual bass enhancement
- a bbe-ish group delay corrction with Biophonic EQ boost.
- precut

auditory fatigue reduction
-reduce signal in frequency that may trigger temporary threshold shift

haas surround
-frequency between f(x1) and f(x2) is always bypassed.
-can apply to side only.

Change-Id: Icb6355ce9b1c99bf2c58c9385c3c411c0ae209d3

The origin of the register value was never
moved in the desired register state due to a typo ('rhs' vs. 'rhd').

While looking at the code, I noticed the action taken
for the register value is another copy'n'paste error
from the ADD opcode above -> it added to the register value
instead of MOVing the current value.

Patch submitted upstream.

cppcheck reported:
[lib/unwarminder/unwarm_thumb.c:473]: (warning) Redundant assignment of 'state.regData[rhd].o' to itself.

Change-Id: I78cdbf37a191007a3bddbaa350b906dbce2fe671

Change-Id: Ia7565dac0f6b9703a5dfff723167620deb218bc3

Detected while looking through the code.
Patch submitted upstream.

Change-Id: I7ebe7b5f5947cf3df1b054d545dba92829f21b99

Also fix a wrong format specifier for an unsigned variable.
Detected by cppcheck, patch submitted upstream.

Change-Id: I9b84d91eeb242ed77b53ecc16252c5b35190bb9f

Detected by cppcheck, patch submitted upstream.

Change-Id: Ieeec9d2e7e2c22d64c94936958f5a4ff02d3548b