- Fixes issue #3 and more

- Fixes issue #3 on AuthService.groovy and AlaWebThemeGrailsPlugin.groovy from the fact that the security.cas.bypass parameter comes as a String and not a Boolean so it requires explicit casting to evaluate correctly in those cases that is set to true in the external config properties file.
- Version number bumped to 0.8.3-SNAPSHOT
- Makes Maven dependency resolution engine ,aether, to be used by default instead of Ivy, which is known to be not very good
- Explicitly excludes servlet-api dependency from rest plugin