Fixes addto_collection error (see urschrei#45)

Adding key_info(), test fixes, doc cleanup

key_info(): 570a1fb

Bugfix release:

Bugfix release

Fixes test to match API change (5707933)
Fix where parentCollection key is added (0da8d06)
Update documentation (4add796)

Adding method to retrieve last modified version, and fix incorrect he…

…ader reference

Adds raw file method (urschrei#37)

Better iterfollow functionality (urschrei#38)
Adds method for single collection retrieval (urschrei#39)

Bugfixes and Pylint conformance

v1.0.0 release for Zotero API v3 compatibility

Updating setup

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