common/hooks.c: adding hooks used by the ubuntu mediaplayer based backend (avoid segfaults)

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>
common/properties.c: also probe property from kernel cmdline (used by mako)

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>
common/linkers: removing Android.mk files are they are not used

And confused the Android build system when building the compat layers.

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>
Merge branch 'upstream-fixes' of https://github.com/rsalveti/libhybris