v3.0-alpha

• Mqtt Log now written to database
• Received Mqtt messages can be viewed in settings
• Added a 'Thing' post type. You don't need to use this, existing shortcodes all still work
• Thing slug can be used in place of mqtttopic in shortcodes
• Thing can be given a lng, lat or geojson shape
• Thing post can include content for thing
• Updated mqttcogs_drawleaflet to draw geojson shape on map for thing
• Updated mqttcogs_shortcode_pre to include topic column
• Updated mqttcogs_data to include 'raw' attribute. If true includes first column of topic