java 7 code compatibility

1. try with resources
2. generic diamond inference
3. multi-catch exceptions
Merge pull request #10 from mehiel/java7-compatibility

Take advantage of Java 7 features.

- try with resources
- generic diamond inference
- multi-catch exceptions
Fix configuration methods missing "static".
Merge branch 'java-7' of github.com:jcoleman/tomcat-redis-session-manager into java-7
Bump version to 1.2.
Fix NPE and ensure changes are tracked accurately. Fixes #13.
Merge branch 'java-7' of github.com:jcoleman/tomcat-redis-session-manager
Update README to reflect Java 7 only going forward.