Add post editing + unliking, better error handling, improve logging in
Add post editing + unliking, better error handling, improve logging in

- 'remember' is set to 1 in getAuthData, so that Edsby doesn't throw us out as much anymore
- LoginError error type added, more types potentially coming soon. If an error occurs on Edsby's end, LoginError returns the Edsby's error, instead of continuing to execute other functions that won't work.
- editMessageInClassFeed works very similarily to postMessageInClassFeed sans-nodetype/nodesubtype and will edit a given post
- unlikeItemInFeed works exactly like likeItemInFeed, except it unlikes an item
ctrezevant/PyEdsby