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

Change-Id: I30219d626316776eb73b4205d63376fa3dbc6361

- Leave original ptr untouched if allocation fails
  (bail out early)
- Behave like malloc() in case ptr is NULL

Change-Id: Ib854ca19bd0e069999b7780d2d9a533ece705add

Change-Id: Id9b50c1fdeca4d87f158da717de8958330f027ef

This file revealed several problems with our ASF parser:

1)  The packet count in the ASF was actually a 64 bit value,
leading to overflow in very long files.

2)  Seeking blindly trusted the bitrate listed in the ASF header
rather than computing it from the packet size and number of packets.

Fix these problems and fix a few minor issues.

Change-Id: Ie0f68734e6423e837757528ddb155f3bdcc979f3

Change-Id: Ie3aa9b208e3f4f17d4d02f11f69839e9b381217d