Check whether variable exist in VariableAction

[ahege]

Is your feature request related to a problem? Please describe. Variables used in VariableActio must be defined.

Describe the solution you'd like Create a parser error if a variable ist not defined.

[ahege]

Added VariableChecker (VariableChecker1_2.cpp)

These checks are performed:

• Check whether the value attribute can be pared into the specific variable concerning datatypes.
• Check whether the variable exists referenced in VariableAction
• Check whether the value of SetAction can be parsed in the spefic data type of the defined variable.
• Check whether a modify action is used for a variable that is not numeric.

These check are not performed.

• Check whether a variable is defined multiple times. This check is neither performed on ParameterDeclarations nor on other names.
• Check whether ModifyAction value fits to integer datatypes. E.g. a value of 3.4 cannot be added to a integer variable.