Data types are not checked in some expressions

[stepanek-m]

In expressions such as 123 < "abc" or true and "abc", data types of operands are not checked and those expressions are parsed without error, even though YARA fails with error when parsing them.

This bug occurs with boolean operators (and, or, not) and comparison operators (==, !=, <, <=, >, >=). I haven't done any deeper research so it is possible that it occurs in some other expressions too.