Creates an independent default workflow store.

[simoneduca]

Field guide uses the default store. Fix #236.

[simoneduca]

Pinging @rogerhutchings too, who suggested this fix, for extra eyes 👀

[shaunanoordin]

• Tested on localhost:3434 with OSX+Chrome52, using modified Assignments page link from lab.wildcamgorongosa.org
• As a Student (zootester1) from lab.wildcamgorongosa.org, if I access an Assignment link (e.g. http://localhost:3434/#/classify/assignment-32/access_token=...), I will be taken to WildCam Gorongosa's Classify page, with the correct Assignment selected, and am logged in if previously not logged in.
  • Functions correctly if Student has already previously logged into WildCam Gorongosa as him/herself. Not tested if, e.g. Student comes from Lab as zootester1 but already logged in as zootester2 at WildCam Gorongosa.
• Confirmed via monitoring Network traffic that the error in #236 does not reoccur - two workflow IDs (the default and the assignment) are NOT simultaneously fetched. ONLY the Assignment ID is requested.
• Confirmed that base functionality appears OK:
  • As a non-logged-in user, I am able to Classify items and access the Field Guide (including specific URLs to a specific animal).
  • As a logged-in user with no assignments, I am able to Classify items and access the Field Guide (including specific URLs to a specific animal).
  • As a logged-in user with a specific assignment, while working on an Assignment, I am able to access the Field Guide. (Without the change in workflow IDs causing any shenanigans.)

Status: LGTM Actions: Merging