Updates the view for the asset map

 - Adds rowspan to mach the number of rows in the variable
   names/variable units
 - Passes in another dict key "varcount" to view to assist in rendering.
Updates the metadata model to pair name and units

 - Wicken doesn't maintain the order between the names and units so this
   is a patch that deliberately fills in explicit metadata.
Adds more comments and descriptives
Fixes stack trace logging
Merge pull request #89 from ioos/units

Fixes the metadata relationship between the variable names and the units