v0.6.17

Improvements:

• Move MXRoom.acknowledgableEventTypes into MXSession (#141).
• MXTools: Update the regex used to detect room alias (Support '#' character in alias name).

Bug fixes:

• Invite a left user doesn't display his displayname (https://github.com/vector-im/vector-ios#646).
• The room preview does not always display the right member info (https://github.com/vector-im/vector-ios#643).
• App got stuck and permenantly spinning (https://github.com/vector-im/vector-ios#655).