also made the friend declaration more specific

and constify one thing

renamed the directory, libname, namespace and main class

- editorial/style fixes
- constify things in trivial cases
- catch exceptions by const reference

exception by reference, indentation fixes.

Conflicts:
	src/lib/dns/tsigkey.cc

- removed redundant white spaces
- added () around 'return'

TSIGKeyFromString is now a direct TSIGKey constructor
TSIGKeyToString is now TSIGKey::toText()