Add PLEP_TEMPERATURE and PLEP_TEMP_MODE hw options.

These are used setting/getting temperature for temperature-
based waveform selection.

Signed-off-by: Andrew Cox <andrew.cox@plasticlogic.com>
initialise plep->dl_handle to NULL to fix error handling

Set the value of plep->dl_handle to NULL in plep_init.  If
the init_with_mode function fails, the dl_handle pointer
was never initialised.  This caused a crash when freeing the
instance and calling dlclose.
use libplutil to read config file + use common logging

* use <plsdk/log.h> and <plsdk/plconfig.h>
* fix includes with <libplepaper.h>
* remove log.h
* look for `mode' in config file when caller passes NULL
* allow mode string buffer to be either static (discover),
  or from plconfig or locally allocated using mode_buffer
  (strdup from caller string)
* use epdc->mode in init_with_mode instead of extra argument
* tidy-up syntax

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
Android.mk: add include path to libplutil
add optional config file path to plep_init

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
fix mode_buffer pointer initialisation

If the mode_buffer is not used, initialise it to NULL.  This
used to cause an error when plep_free was called as the pointer
may have been initialised to a random value.
rename PLEP_TEMP_MODE to _TEMPERATURE_AUTO + add Doxygen

Rename PLEP_TEMP_MODE to PLEP_TEMPERATURE_AUTO, which controls
whether the automatic temperature mode is enabled.  Also add some
Doxygen comments for the PLEP_TEMPERATURE and
PLEP_TEMPERATURE_AUTO values.
epdc-noep.c: add stubs for the hardware options

Add `noep_priv' struct to contain an array of integers for the
hardware options, and implement epdc->set_opt and epdc->get_opt.
This enables testing the plep_set_hw_opt and plep_get_hw_opt
API functions.
Android.mk: fix include path to libplutil
ChangeLog v1.8 -> v1.9