Fix contextComplexJ so that it can be loaded in parserCustomization.pl, and so that it can allow or disallow each of the i and j notation independently.
Fix problem with error messages when a restricted input format is required.  Make sure constants display their TeX forms correctly.  Force the constant i into the given context so that it produces the proper class when evaluated.
Make sure the changes to teh context actually take effect.
Merge pull request #136 from dpvc/patch-complex-j

Fix contextComplexJ so that it can be loaded in parserCustomization.pl, ...

I tested this, both using global configuratoin changes and local ones.  I was able to require students to enter answers using i or j or either.  The display of equations, answers and correct answers all respected the appropriate flag.