Relocate the default PBKDF2 iterations to tuf.conf
Store in .key files the number of PBKDF2 iterations used
Update test_keystore.py following .key format and keystore changes
Update unittest_toolbox.py following .key format and keystore changes
Minor code updates to keystore.py
Continue minor edits of PyCrypto changes

Improve the comments of keystore.py and rsa_key.py.
Merge branch 'develop' of https://github.com/theupdateframework/tuf into develop
Resolve conflicts from demo 2 updates
Fix typo:  missing the word 'key'
Fix ignored placeholder variable names

'junk' signifies that this variable is not needed and thus discarded, however, it hides what is returned.  Include the junk and what is returned so the variable name is more descriptive.
Fix how the private key is checked prior to verifying a signature
Fix link that discusses setting the time for all logging formatters
Add missing docstring to remove_console_handler() and minor edits
Fix print statements and help with python 3 compatability

test_arbitrary_package_attack.py.
Fix extraneous new lines in test_delegations.py
test_endless_data_attack.py: Fix indentation

Also help with Python 3 compatability.
test_extraneous_dependencies_attack.py: python 3 compatability

Also fix print statements.
test_indefinite_freeze_attack.py: Python 3 compatability
test_mix_and_match_attack.py: Python 3 compatability
test_replay_attack.py:  Python 3 compatability

Also fix indentation.