Correct the prototype of the method getClassName.

Use the dedicated macro to this purpose.
The error came from the fact that the method was not declared
as const. The consequences were that the following python orders
were possible:

mytask = TaskInequality ('mytask')
mytask = Task ('mytask')

The second line should crash but doesn't, because the method getClassName
called is the one of the mother class.
For normalization purposes, use the DYNAMIC_GRAPH_ENTITY_DECL macro everywhere.
Add the command line 'remove', alias of 'rm'.

Again, for homogeneization purposes.
Remove deprecated method commanline.
Synchronize.
Add the display method for normalization purposes.

This allows to do 'print solver' in the python interface.
The 'dispTask' method is kept for transition purpose.