Makefile: add support for ccache
synaptics_3k: sweep2wake, stroke2wake & doubletap2wake

Includes a hack to fix in-call behavior. I made proximity
sensor to report to synaptics_3k its status so I could skip touch
handling altogether when proximity sensor status is "near".

Ported i2c_syn_read() function from endeavoru kernel to fix sleep state
problems. No retrying for i2c_transfer() lead to device not waking up
properly.

Some of the code and ideas taken from these repos/commits:
https://github.com/Mustaavalkosta/htc7x30-3.0/commit/adec359240f0d5fa72e42e5732e53a3f27269dff
https://github.com/n3ocort3x/endeavoru_3.14
https://github.com/TeaMSeven/android_kernel_htc_m7-sense
https://github.com/dorimanx/Dorimanx-SG2-I9100-Kernel/

Additional thanks to @pnoire for throwing refreshing ideas at me,
testing and listening to my cursing when nothing worked, lol.