tf700t|tf300t: libhealthd: Add dock battery support

Added a new HAL for libhealthd and removes the obsole asusdec one

Dock battery patchset chain:
base: http://review.cyanogenmod.org/#/c/55349/
native: http://review.cyanogenmod.org/#/c/55028/
healthd: http://review.cyanogenmod.org/#/c/55029/
settings: http://review.cyanogenmod.org/#/c/55212/
tf700t: http://review.cyanogenmod.org/#/c/55030/

Video (battery styles): https://www.dropbox.com/s/a7dp3glb7lv1zcg/dock_sdcard01.mp4
Screenshots:
 * No dock: https://www.dropbox.com/s/2yvngdaqok32xiz/dock_sdcard01.png?m=
 * No charging: https://www.dropbox.com/s/ezghtgoedei17oj/dock_sdcard02.png?m=
 * Docked no charging: https://www.dropbox.com/s/7fasc05fw5ylfxi/dock_sdcard03.png?m=
 * Docked charging: https://www.dropbox.com/s/x37vrhxzd075f7p/dock_sdcard04.png?m=

Change-Id: I6c29e2728959d5624e8f9a110eecdc79a770ae15
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>

Conflicts:
	BoardConfig.mk
tf700t|tf300t: libhealthd: fix pluggable status

The board only should report a pluggable status if and only if the status sysfs
reports a valid charging status

Change-Id: I4d71ca280d7d459a1ae15774bd264c228d9d5056
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>