~~~~~~~~~~~~~~~~~~~~~~~~~~~
- add children argument to Account constructor
- add a new example (used as answer to http://stackoverflow.com/questions/17055318/create-transaction-in-gnucash-in-response-to-an-email/ )
- add a new example showing how to export Split information to pandas DataFrames
- fix an error handling in retrieving currency exchanges in quandl
- fix py3 bugs in dataframe functions
- fix type and source of Pricers to be compatible with GnuCash
- add a Price when entering a commodity Split
- set microsecond to 0 for all datetime
- add pandas for requirements-dev
- add tests for deletion of transaction and for dataframe functions