Config::getParam* with more than one entry

[xrubio]

Currently the system only allows to have one entry for each param in the config, but it could be the case where there are several entries of one type. For example:

We need some method to iterate over the list, such as: for( auto entry : getEntry("agent")) { Point2D pos; pos._x = getParamInt(entry, "x"); pos._y = getParamInt(entry, "y"); }