Update appveyor.yml

Merge pull request #114 from noobot/json-reader

Json reader can be constructed with different paths

Further cleanups around new extensions code

Merge pull request #105 from AshleyPoole/f/update-slack-connector

Update Slack Connector to 4.1.48

Update nuget packages

Build with full VS 2017

Fix path reference for build

Merge pull request #88 from noobot/mega-slack-connector-upgrade

Upgrade SlackConnector and remove old reconnect method

Merge pull request #85 from noobot/fix-always-match-issue

Fix always match issue

Merge pull request #83 from noobot/helper-methods

Add some helper methods for valid handles