Added a complex comparison sample scenario.
Moved Semantic Comparison sample classes

to sub-folder, and made them public. The next step is to make them
extensible with Constructor Injection, so that each of them are decoupled
from the other. This will (hopefully) better demonstrate how a loosely
coupled system can be built.
Opened SemanticElementComparer for extensions.
Made SemanticReflectionVisitor looser,

because there was no reason it had to expose a strongly typed sequence of
comparison values in order to do its work.