Add support for new Messenger Platform social plugins

[stevegeek]

Adds the new Facebook Messenger platform plugins to the plugin list, 'fb-send-to-messenger' and 'fb-messengermessageus'

See https://developers.facebook.com/docs/messenger-platform/plugin-reference

[pc035860]

@stevegeek The messenger platform plugins are only available in platform version 2.6. Can you upgrade the default SDK version parameter to v2.6?

https://github.com/pc035860/angular-easyfb/blob/master/src/angular-easyfb.js#L93

[stevegeek]

@pc035860 Ok thanks for the feedback. Done.

[pc035860]

Great! Thanks for the PR.

[stevegeek]

@pc035860 thanks, when do you think you might bump the version to add the support for this?

[pc035860]

@stevegeek Just published!

[stevegeek]

@pc035860 Thanks for the swift response! :)