Constant/expression in step priority causes missing step candidates

[rimesc]

The code for parsing the priority attribute of the JBehave java annotations assumes that the value is an integer literal. Some of our code uses constants or simple expressions based on constants. When the plugin encounters one of these, it throws a ClassCastException (which gets swallowed and never appears to the user) and stops parsing the file. The remaining steps are treated as missing.

Realistically, I don't think there's an easy way to evaluate the priority in these cases without involving the java compiler, but an improvement would be to use the default priority (or none at all) and at least parse the rest of the file.