Renaming ctor helper methods in the testing suite to reflect the concrete implmentations they construct.

Tidying BiMap. Adding class for tracing debug info, since NUnit and its adapter are very good at swallowing up any potential ways of printing debug info.

Fixing test name display issue and adding a parameter and property for name display purposes in NestedIDictionary.

Fixing bug in MultiBiDictionary where a missing not operator in RemoveKey would mess everything up; Explicit interface tweaking; Constructor passing comparers to new properties in the instance.

Numerous changes to NestedIDictionaryBase: Adding new tests, Adding constructor delegates to the constructor to allow flexible creation of needed collections, Moving constructor parameters into a data class. Changing MultiMap test classes to accomodate the recent modifications.

Adding generic (as in nondescript, not type generic) helper class. Should split into properly named static classes once it gets more populated.

Fixing bug where ICollection<KeyValuePair<TKey, ICollection<TVal>>>.Contains in MultiMap would throw a null error.

Changing rule about pascal case public fields. Might reconsider. I'm used to all fields, regardless of accessor, being camel case in order to distinguish them from properties.