the previous commit was wrong.

Fixes #350

It makes $r available in the code given to CtBehavior#insertBefore().

in other words, java.lang.invoke.MethodHandles.Lookup.

Applied fix for #152 "Wrong modifiers returned for nested classes" as suggested by @pietrobraione.
Includes unit tests for all access modifiers and static.

As per question raised in #161 passing 'this' reference for CtField value new object instance.
Also added assert for testing referncing 'this' for newly added field.

Applied parameters and squashed all compiler warnings.
Changed loops to enhanced for where appropriate.
Fixed SoftValueHashMap:
Made it a raw type.
Overwritten implementation of the `get` method correctly unwrapped the reference but the methods
`containsValue` and `entrySet` needed to be fixed.
Implemented the remaining outstanding methods from the `java.util.Map` contract `values`, `putAll`
and `keySet`.
Dropped `AbstractMap` inheritance as we were not inheriting anything anymore.
Changed internal map to `ConcurrentHashMap' to be atomic and parallel safe.

Found original unit tests from jboss retro which are now updated to reflect the javassist
versions of the scoped pool classes. Added tests for the SoftValueHashMap including
test which overloads the heap to ensure the cache cleans itself appropriately.

Proves that you cannot access restricted functionality then goes ahead and
mock test all 3 exposures JAVA_9, JAVA_7+ and OTHERS by changing the
private static final class referenced default chosen on initialise.

With the unit tests warnings were squashed by suppressing them with SuppressWarnings annotations, instead of
reparing the issues as was done with the source. Reasons being...
 * The tests might be relying on the types as they were defined.
 * If the tests were written to test against the correct forms they would've/should've stipulated those.
 * Even unused members might be important to tests so we attempt to change as little as possible.

Changed to org.junit.Assert.