prototyped setting up the bus and service inside the specs

found a problem where GetConnectionUnixProcessID returns 0
don't try service pid, kill it by Exec name
use around(:each) to restore the env variables
factored out ASessionBus.session_bus_address
Renamed test/ to spec/

to enable running the specs with plain "rspec".
It still does not work because it expects spec/tools/test_env to set
things up. Use `rake spec` for now.
Merge branch 'master' into test-env-internalize
fixed up config_file_path after merge
moved helper functions to spec_helper
Inlined the examples in the documentation.

Online docs at
http://rubydoc.info/github/mvidner/ruby-dbus/file/doc/Reference.md
was not rendering the {include} directives.
rake doc:examples will extract the inlined examples.
Avoid be_true be_false for RSpec 3 compatibility.

http://www.bengribaudo.com/blog/2014/01/17/2674/rspec-be-true-be_true-are-different
Service#unexport fixed to really return the unexported object
Merge branch 'rspec3'

Conflicts:
	test/bus_driver_spec.rb