Grid_Basic: shouldn't return value
TestApi: set totals column
Grid_Advanced: nasty, nasty bug :)

current_row_html should be used here to overwrite everything in current_row.

Be aware that this commit will conflict with another pull request I made today ! Both need to be merged somehow.
Merge pull request #411 from DarkSide666/patch-6

Fixes for grid totals and tests API