Merging v0.10 changes from development to master
* Added a way to handle non-xml errors (#515)
* Added Webhooks endpoints for create, delete, get, list, and test (#523, #532)
* Added delete method in the tasks endpoint (#524)
* Added description attribute to WorkbookItem (#533)
* Added support for materializeViews as schedule and task types (#542)
* Added warnings to schedules (#550, #551)
* Added ability to update parent_id attribute of projects (#560, #567)
* Improved filename behavior for download endpoints (#517)
* Improved logging (#508)
* Fixed runtime error in permissions endpoint (#513)
* Fixed move_workbook_sites sample (#503)
* Fixed project permissions endpoints (#527)
* Fixed login.py sample to accept site name (#549)