encore_defconfig: enable CONFIG_LOCALVERSION_AUTO

This will put the SHA1 hash of the commit from which the kernel is built
into the version string, making it much easier to pinpoint the exact
source code associated with a particular bug report.  CONFIG_MODVERSIONS
(already enabled) means this change won't break kernel module
compatibility unnecessarily.
Add a separate defconfig for CM 10.1/Android 4.2 builds

The 10.1 buildconfig has CONFIG_PANEL_BOXER_TRUE_COLOR=y and
CONFIG_ST_HCI=y set.  Meanwhile, remove CONFIG_ST_HCI from
encore_defconfig, since it's not needed on Android < 4.2.