ENH: Add serialization to account
BUG: Fix flake8
BUG: Hide account methods from repr
ENH: Updated naming scheme of serialization methods.
MAINT: Updated the naming scheme from reconstruct to set_state
ENH: Allows history to be dynamic and grow the container at runtime.

Previously, all specs had to be pre-allocated by using the 'add_history'
function. This is now no longer required and instead serves as a hint to
the HistoryContainer to pre-allocate the space for the given spec.

History can grow by increasing the length for a frequency, adding a
frequency, or adding a field. It can grow with any combination of
these.

HistoryContainer now is aware of the data_frequency of the algorithm,
and no longer uses the daily_at_midnight flag; instead, this is the
default behavior.