Revert "Unmark EdgePartition fields as transient"

This reverts commit 5d7cd9343ec6aab2e9b835232e10e87ac4943c90.
Revert "Make everything in an RDD serializable"

This reverts commit 68d20b839dff4629522bc6091ad63a4f4a27947a.
Revert "Register PrimitiveKeyOpenHashMap"

This reverts commit 5fca182108368179c117d1915513a4e491aba191.
Revert "Delta encoding for VertexAttributeBlock"

This reverts commit 00c77d4726b3d26c2028be938e199a31c2f28a34.