Rewrite implementation of some ESAPI classes to remove Java 8 dependencies

[kwwall]

The current minimal baseline for ESAPI 2.2.0.0 is supposed to be Java 7. While the ESAPI pom.xml specifies and to use 1.7, we've been a bit lazy and haven't bothered to specify a '-bootclasspath' that refers to a Java 7 rt.jar file. As a result, we ended up unintentionally ended up using a few Java 8 (and later) packages. Those need to be removed if ESAPI can be used with Java 7.