Add comments
Changed C.Var behavior. When array size is empty, an empty array size is used (example: char foo[]="hello world")
Fix pointer of pointers creation (regex parser and display style)
Fix variable declaration processing of pointers of pointers.
Fix display of pointer types
Add negative unary operator overloading for C.Expr: it adds parenthesis around the given expression.
It can be used to obtain the same parenthesis in C code as in Python code.
Add docstrings for overloaded operators