Modify the spec of the Parser class
Modify the spec of the Parser class

The specification of the Parser class has been modified in order to be
able to parse the program clause:

- The new method #parse_program has been added in order to parse the
  program clause.

- The method #parse has been added in order to parse a complete a
  complete input flow.

ludokng/puppetshow,ludokng/puppetshow