Expose CZML helper functions.

#1080 accidentally removed some helper functions needed for custom CZML processing.  I expect these function to go away in the near future, but they are definitely needed for now in apps that use custom CZML.

CC @emackey
Merge remote-tracking branch 'origin/master' into expose-processPacketData
Merge pull request #1110 from AnalyticalGraphicsInc/expose-processPacketData

Expose CZML helper functions.