[trac2945] miscellaneous doxygen warnings worked on

Still have lots to do.
Some of these marked with TODO indicating needing further work
(but better than it was before).
Don't crash with missing TSIG name
Remove hard-coded (and unecessary) TSIG key from error message.
[2945] Add missing doxygen comments
[2945] Update Doxygen reference to isc::ConfigData::getFullConfig()
[2945] Update Doxygen reference to isc::ConfigData::getFullConfig() (contd.)
[3239] Update comment
[3239] Expand documentation on configuration data type syntax
[3239] Update exception messages returned when types mismatch

We include the type of the received value so that the user can see the
type mismatch more clearly from the returned exception message.
[2566] Include logging maintenance guide into BIND 10 Developer's Manual

Convert the old logging "README" file to Doxygen format.  The opportunity
was taken to expand and edit it at the same time.
[2566] Review - minor potential cleanups
[2226] Return rcode=REFUSED to serve qtype=RRSIG queries
[2226] Add unittest and lettuce test for qtype=RRSIG query
[2517] Add tests for RRSIG toWire() methods
[2951] Fix bad concatenation to construct wildcard name (for root zone)
[2951] Add lettuce test for non-existing name in root zone from SQLite3
[1796] Move A_AND_AAAA to the Query class
[1621] Set maximum version correctly in logger_example.cc
[1516] Add sender details when AUTH_UNSUPPORTED_OPCODE is logged
[2518] Move NameParserException to exceptions.h header