Added professional support notes
Added professional support notes

As per Tidelift integration:

 * a link to the Tidelift subscription was provided
 * a way to contact the author for professional consulting was added

Gitter support was removed, since I'm no longer able to actively follow Gitter as well. I'm fine with new issues with questions being opened: easier to search, more useful to future users as well.
Ocramius/ProxyManager