common: Disable multithreaded dextop on RELEASE and SNAPSHOT builds

This needs some more work before it can be considered stable enough
for use on these builds.

Change-Id: Ic80603cc59623da878875e40de92bda5caef3331
ota: Validate any installed data's signature against our own

Try to prevent incompatible-signature system quirkiness

Change-Id: I73402d963a1b57ad0ee3c68ced4f2d7f074f927f
common: Set property for the CM releasetype

Set ro.cm.releasetype based on the deteremined releasetype of the
build.

Change-Id: I2c1aa7181f42342594bd6d5dc5f5252220ed3497
Merge pull request #2 from CyanogenMod/cm-11.0

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