Port core code from Box-Windows-SDK-V2

rename projects/solutions and set new guids.
Add CoursesManager, remove all others.
Add Course/CourseRequest, remove all other models.

Also rename some stuff to strip out 'Box' prefix.
Rename classes; remove affordance for OAuth1
Stub out Courses, Accounts, and Users managers.
Fill out the UserProfile model.
Support gzip/deflate compression by default.
Update UserProfile/Account models, managers.
AcceptEncoding header should always allow compression.
Make Client.*Manager initialization lazy to reduce footprint.
Clean up method.
Add target domain to CanvasConfig

Canvas authorization requires that a particular auth token be used in
conjunction with a specific *.instructure.com/api/v1 instance.
Fill out the Account model.

Experimentally derived due to incomplete API documentation.
Change Account.*StorageQuota type to int.
Add AccountsManager.GetAll deserialization test.
Align test namespaces core library namespaces.
Fetch all courses for an account.
Correctly format parameter arrays in query string.
Add optional params to AccountsManager.GetCourses
Refactor