Revert "Temporary backwards compatibility for Guava Supplier with usage warning to switch to Property"

This reverts commit 7d5a7bd12bc516c3181c2975e40b1763d1ba046a.
Revert "Remove use of Supplier in public API's and switch to an internal Property class"

This reverts commit eabad8cf46c03dc846534989d91677f9f41af824.
Merge pull request #174 from elandau/bootstrap

Revert change to remove Guava's Supplier from public API's