Debugging Login.
using boost::diagnostic_information
Moved user credential and authentication code to Common.
Fixes compilation error on Linux (Gcc)
Merge branch 'demo' into next

Conflicts:
	include/maidsafe/session_handler.h
	src/maidsafe/tests/session_handler_test.cc
updated inline with passport changes.
Style fixes
updated to take maid and anmaid as pair.
cleanup