Small hacks to get the editor working

Changes not shown in original graph, but convolution works with the
new value.
Merge branch 'editor-test'
Resample function after edit
Updates small preview graph
Updates graph in red & blue sectors on edit
Merge pull request #1 from Jamil/master

Merging changes from Jamil.  Thanks for the quick fix :P   I guess this will have to do for now.  When we have time we should make this really nice so future 216 students can use it.  I want to added convolution animations too!