* Added InstlInstanceSync_p4 for syncing from Perfroce
    * Improved support for syncing from perforce.
    * New type of defaults file by repo type, i.e. P4.yaml, URL.yaml. Currently added P4.yaml to defaults folder.
    * New utility function: P4GetPathFromDepotPath to get teh local disk path from p4 depot path.
    * Useage of $(LOCAL_REPO_SOURCES_DIR) instead of $(LOCAL_REPO_SYNC_DIR)/$(SOURCE_PREFIX) - because p4 does not need SOURCE_PREFIX.
fixed typos
merge from p4 branch