"This, for chaining."

Okay, a few new things have been added in this commit.

– As the title of this commit suggests, “stacking” has been replaced
with “chaining” for methods that return “this.” This is a more accurate
way to say it, since we are “chaining” methods, not “stacking” them.

– Preview hiding, although always being advertised as a feature, has
not been a configuration option; this has been fixed and implemented.

– Users cloaked by the above feature will not be uncloaked if they were
already hidden previously.

– ChangeSubscribers have been a bit better implemented. Now,
InvocationTargetExceptions and IllegalAccessExceptions will fall into
the debug system. The subscribing method is now actually invoked;
that’s pretty useful.

– DateComparison no longer uses loops. This makes it faster and more
succinct. What more could you ask for?

– The messages file has some more messages.

– TimeLexer will automatically take out angled brackets, “before,”
“since,” and “after” from input which contains commas (i.e. one that
contains BOTH a “before” and “after” clause). This keeps the parser
from being confused. Also, since the time region cannot be a
disjunction (i.e. the time frame between the two given times is
EXCLUDED, not included), it makes little difference anyway.