Report errors during Telamon-gen parsing

[ulysseB]

Currently, Telamon-gen generates a backtrace when it encounters a user error. This makes it hard to use. It should report errors with line and column numbers instead.

Remaining actions:

• Separate declaration and definition
• Sets type checking and declaration
• Generic choices type checking
• Enum type checking and declaration
• Integer type checking and declaration
• NumericSet type checking and declaration
• Counter type checking and declaration
• Constraint type checking and declaration
• Trigger type checking and declaration
• Quotient sets type checking and delclaration

[ulysseB]

Here are my comments on the current error checking:

• many function could be factorized between IntegerDef, EnumDef and CounterDef. All three statements define a new choice so it makes sense. Moreover, the names of IntegerDef must not collide with the names of EnumDef and CounterDef.
• Choice parameters should only be checked once sets are defined. Indeed the set may be defined after the enum in the input file.
• the name parametric is used where it should be parameter
• Some structures could be made private
• Add doc comments to structures and enum variants