Ruby 1.8.6 fixes
Avoid 'warning: assigned but unused variable' warn

When $VERBOSE is true ruby will log error for unused variables, this
error can be suppressed by prefixing variable by '_', or having variable
named '_', which is canonical signal for 'unnecessary'

(refer to commit c9528f6a9e3157b349d3d81d20b9b4047ee9ff63 as well)
Added TLS support
Merge pull request #36 from yourkarma/tls-support

Added TLS support
Merge branch 'master' of github.com:njh/ruby-mqtt
Merge pull request #33 from ytti/master

Avoid 'warning: assigned but unused variable' warn
Fix to #36, so that openssl is loaded on older rubys
Removed unused variable
Merge branch 'master' of github.com:njh/ruby-mqtt

Conflicts:
	lib/mqtt/packet.rb
Initial work to add support for mqtt:// URIs (issue #31)
Moved parsing of String to URI into parse_uri
No longer defaults to ‘localhost’ if there is no broker configured
Added support for using the MQTT_BROKER environment variable
Improved documentation on the Client initialize method
Changed to using stings instead of symbols for instance_variable_set
Changing to using let() in specs instead of setting instance variables in before(:each)
Allow passing array of topics to Client#unsubscribe (fixes #37)
Allow more combinations of arguments to be passed to a new Client
Removed the deprecated clean_start methods
Made the ruby authentication example less specific to 2lemetry (fixes #29)