Fix AskSage to work with the accepted_tos option, and to print any errors.

With sagecell.sagemath.org, the user will now have to specify accepted_tos=>true, which indicates their agreement to the server's terms of service.
Make the sage interface support getting back multiple values in json format

Now, any values you want back, put them in the python WEBWORK variable.  The return from AskSage is a hash corresponding to WEBWORK.
Update AskSage
this combines contributions from Jason Grout and some
primitive debugging features from M. Gage
Fix error order of defining variables.
Merge pull request #77 from mgage/release/2.8_asksageupdate

Release/2.8 asksageupdate