fix(Tests): Use fork of csv-js

Because the parent repo is broken.
fix(Tutorials): Point back to angular 1.2.26

For some reason in 1.3 ngClass is refusing to change with $scope alerations on
the tutorials but it works fine outside of them. Probably has to do
something with grunt-ngdocs or our custom changes to it.
fix(GridRenderContainer): Redraw with scroll %

Use previous scroll percentage to redraw, not the previous scrollLeft
value. The scrollLeft is too imprecise and is causing large canvases to
redraw out of place. To reproduce, you could scroll the "Horizontal
Scrolling" tutorial all the way right and then sort (or manually call
grid.refresh()). Changing redrawInPlace() to use the previous scroll
percentages fixes the issue.

Fixes #2357
chore(Header/Footer) Remove group-panel elements from header and footer.  Grouping should be in it's own feature module when it is developed
Enh(headers): add sectionHeaders grid option for enabling section headers
Enh(headers): add getSectionWidth method for section header rendering
Enh(headers): add template for recursively rendering section headers
Enh(headers): fix getSectionWidth to skip invisible columns
Enh(headers): fix template to only render visible columns
Enh(headers): add isSectionVisible method for checking if section should be rendered
Enh(headers): fix template to only render visible sections