Added more bitcoin tests
Added util test file
Added mnemonic to seed tests
Added a lot of tests for SimpleConfig

Refactored the SImpleConfig class a lot to make sure the behavior is
always defined.
Do not use mutables as default values!

This blog article explains why (just an example, many other articles
discuss this ad nauseam):
http://pythonconquerstheuniverse.wordpress.com/2012/02/15/mutable-default-arguments/
Travis now excludes "gui"

Instead of selectively including valid packages.
Added more tests for edge cases.
System config should never be None
Added tests for the system config function.
Added more tests for user config parsing.
estimate fee using number of outputs
Fixes previously introduced bug

The passed in command line options were saved to the user config.
Fixed docstrings
Ported most of the bip32 primitive to support testnet
All tests pass, bip32 functions now take "testnet"

The testnet param determines if the key mangling should be done for
testnet or for normal bitcoin.
Added tests for the xpub_from_xprv function.
Made deserialize_xkey() smarter.

This avoids the need to pass the testnet flag to it (it now detects what
type of key it is, and deserializes accordingly).