change minimum/default TP from 4.20.5.Final-SNAPSHOT to 4.30.0.Alpha1-SNAPSHOT so everyone will build w/ Kepler; add TODO about moving maximum to 4.30.1.Alpha1 once M5 bits are out next week
JBIDE-13266 Enable pack200 in build

Artifacts now generate their related .pack.gz file, and
component sites now include pack.gz as well