WebWork should read theme.properties the same way as it reads tempalates.

Currently webwork reads templates using the following order
- read from the file system (if templatePath servlet context init-param is specified)
- read from webapp path
- read from classpath

However the theme.properties are currently read in the following order
- read from file system
- read from classpath
- read from webapp path

I guess we should make them consistent, such that the order of reading theme.properties is the same as reading templates. The changes needed is in BaseTemplateEngine's getThemProps(Template) method