Defines balance::SCCS and incorporates some dependencies on different SCCS's
Merge branch 'balance_sccs' into develop
Create new base class adt::Exception, it will be useful when we define dbms::DatabaseException.

adt::Exception does not inheritance from boost::exceptions due to strange compiler errors.
Defines new template adt::Average <_T> to calculate the average value for a
serie of numbers.
Defines new template class adt::DelayMeter and fix one small issue with includes at logger/TraceMethod.hpp
Defines new utility to write traces with critical level
Defines new method xml::Node::createText (const std::string&)
Very first version for wepa::dbms library, It didn't have any test but it was compiled
successfully.
Renames dbms::Abstract::Type as dbms::Abstract::datatype
Changes std::vector by boost::ptr_vector to store connections and statements.
First revision after firt unit test.

setter and getter must be aware of nullness
Removes dbms::Date::operator=
Changes dmms::Abstract::setNull(bool) by to different method isNotNull and isNull, to activate and
deactivate the null indicator.

Defines new method dbms::Abstract::hasValue () to inform about the null indicator.

All getter must throw an exception when the data is null.
dbms::Integer test unit
First version of unit test for all dbms::datatypes
Substitutes operator= by the corresponding setValue. Improves checks in dbms::String::setValue
Substitutes the boolean isCritital used when creates a new statement for a new enumeation dbms::ActionOnError.
New revision loop for the classes from wepa::dbms
Write a better explanation when the signal handler for child termination can not be installed
Defines new method to down cast from dbms::Abstract to any other inherited data type
dbms::Connection method only will be called from dbms::GuardConnection