on fix-util-py branch.

Added num_confirmations parameter to gather_inputs (default=1, which is the value that is currently hard-coded.)

Added initialize_chain_clean function to allow user to create an empty chain.
Merge pull request #1 from mrbandrews/fix-util-py

on fix-util-py branch.
Merge pull request #2 from mrbandrews/development

Development to master - util.py