Added tests for the conditional operator, operator precedence,
modules ("module" and "export" keywords, and the "::" operator), and
for the "copy" keyword.
Also improved tests of max/min values of int, count, and double constants.
Added tests of all built-in Bro data types (including different
representations of constant values, and max./min. values), keywords, and
operators (including special properties of certain operators, such as
short-circuit evaluation and associativity).
