[Engine-XMPP] Addressed issues raised in PR #27

trace important callbacks

properly log messages

pretty-print xmpp commands

only make CommandX public

code formatting

bugfix: messaging to all high-priority contacts is now proper

undo removal of meebey commit

use the new messagebuilder feature that allows string formatting of ContactModels

RemovePerson + AddPerson = UpdatePerson

don't write default "private" modifier of functions

refactored protocolmanager command calls

use AppendFormat because MessageBuilder.AppendText cannot parse PersonModels

first iteration of thread safety in XmppProtocolManager

remove ContactChat locks as they are now obsolete

removed overprotective synchronizations

no leetspeak in function names

InviteToMenu uses ThreadPool for InviteCommands

constructor doesn't need synchronized

don't make functions public that noone else calls

don't use private, it is the default

for loop inside try to prevent loop from throwing

most useless use of String.Format ever

we have a super cool parser for ContactModels!

no .net 4.0 features!

code format nitpickery

String::Length is not a function

AppendText does not know how to parse ContactModels
[Engine-XMPP] Moved JabberClient instantiation to ctor
[Engine-XMPP] Fixed and moved proxy settings to ApplyConfig()
[Engine-XMPP] Updated copyright info
[Engine-XMPP] Fixed build on Mono 3.0.6