CBMC Version check

additional refactorings to cleanup interaction with CBMC
Improve handling exitvalues coming from CBMC
add icon in view and launch configuration
Verify the compiler is installed
Initial support for struct and array
Add readme
Add args4 and antlr to the feature to force inclusion in repo
Fix var-update command
Remove warning
Handle exceptions from commands
Cleanup code of variables related commands
Missed file
add antlr repo
Implement traversal of data structure for VarUpate

- Add a new method comparing two values
- Add a flag to specify on the obtention of user friendly value
StackListLocal must return complete value
Remove full_lhs and full_lhs_value from the model
Fix incorrect parameter name in return value of VarInfoPathExpression
command
Reorder arguments in the return value of VarListChildren
Marker representing the error in the program set to transient
Remove use of non API