TinyBRL 1.2

     - Switch 'MDPException' to 'AgentException' in Agents (and its derived
       classes)
     - Add 'AgentException' and 'MDPException' to 'dds::simulate()' function.
     - Allow the UCB1 algorithm to discard any arm for which an std::exception
       has been thrown when it has been drawn.
     - Added an optional method 'freeData()' to the Agents. This method will be
       called when the Agent has finished to interact with the current MDP,
       offering the opportunity to free unnecessary data (useful when dealing
       with OPPS-DS which has to keep an instance of all Agents of the set of
       candidate strategies).
     - Revision on error case in 'learningOffline_aux()' of several agents
       (when an Agent only support Dirchlet distributions as a prior).
     - Options '--backup_frequency' and '--refresh_frequency' are expressed in
       seconds (it was in milliseconds previously).
     - Move 'Formula' package into 'utils' package
       ('Formula' is not serializable anymore).
     - Minor change in agents' names for 'OPPSDSAgent' & 'OPPSCSAgent'.
     - Split the variables used by 'FormulaAgent' in indepedent classes:
       'QMean', 'QSelf', 'QUniform' (integrated in dds namespace).