Release/2.8 asksageupdate

These are Jason Grout's fixes, corrected to allow for a clean merge.  I believe I've done the corrections
correctly -- Jason can double check.

There are additional error checks -- both a debug option which I put in and
allows you to trouble shoot even when Sage is returning some kind of result 
a try/catch block (implemented with eval {} ) which catches errors thrown by Sage. 

I've checked these on a few dozen of the sage homework problems written by John Travis
and they appear to work.