added oauth twitter integration by rest

integration oauth with facebook

[FIX] Chat Message Reactions REST API End Point

adding end to end tests for chat.react endpoint

[NEW] Allow sounds when conversation is focused

[NEW] API to fetch permissions & user roles

[NEW] REST API to use Spotlight

Update to meteor 1.6.1

[FIX] Messages can't be quoted sometimes

[FIX] GitLab OAuth does not work when GitLab’s URL ends with slash

# Conflicts:
#	package-lock.json
#	package.json

[FIX] Close Livechat conversation by visitor not working in version 0.61.0

[FIX] Formal pronouns and some small mistakes in German texts

[FIX] Facebook integration in livechat not working on version 0.61.0

[FIX] Weird rendering of emojis at sidebar when `last message` is activated

[NEW] Option to proxy files and avatars through the server

[BREAK] Remove Graphics/Image Magick support

[NEW] Allow request avatar placeholders as PNG or JPG instead of SVG