UI: node details improvements refers #132
 * avatar
 * likes
 * dislikes
updated requirements
nodeshot.community.participation: user details in comments
* participation now dependent on profiles
* user details in comment serializer
UI: added User model
UI: node details step2 - refers #132
* no dummy data
* show relationships
* show comments with avatars
UI: permalink on node details - refers #132
fixed API login user inactive case bug
minor API code cleanups
UI node details: like & dislike proto #132
UI node details: users can comment #132
DynamicRelationshipsMixin now accepts functions
"has_already_voted" in API node detail relationships
UI node details: highlight if already voted #132
removed django version from .travis.yml
UI node details: hide user info if user is null #132
UI: remember "stay signed in" checkbox + minor improvements
UI: can't vote unless logged in, refers #132
UI: rate node, refers #132
updated requirements.txt & .travis.yml
nodeshot.community.profiles API: added location attribute
+ minor improvements and cleanup