Account creation is now available through CLI interface.

When item are not found in Account List use case, exceptions are
correctly catch and return appropriate response failure to user.

When items (such as Account or Operation) are not found in get operations,
exception ItemNotFound is now raised instead of simply return None.

list command will list all available commands. A command is wrapped in a
single Python module inside openbudget.cli package, so list is
completely dynamic.

Start to build main OpenBudget user interface.

Coverage report now taking into account branch.

Finalize pager in account request.
Only sort functionnality is not implemented on account listing.

Avoid `unexpected behaviour` when a non-string is given in MalformedRequest
exception

Begining of Account List use case implementation:
 * allow retrieving of a single account
 * allow retrieving all account
 * allow limiting to n first account

Create structure for all usecases call that acts as message passing from
view to model and back to view.
Create base class for all input request and output response, used in
usecases.

Create interface to remove account and/or operation.
Implement it in memory implementation of storage

In-Memory repositories is now able to register account and
operation.

Sphinx is now able to build documentation from docstring

Create ConfigurationError exception to track error in OpenBudget
configuration.

Common implementation of currency code to currency object convertion
with right exception throwing in case of error.

Only tests folder was checked.
Add openbudget and setup.py to flake8 and pylint tools