fixes #130 - divide by zero in dasbboard

fixes #80, fixes #106 and fixes #128

fixes - #120 - Include timestamp of dashboard page generation

fixes #89 - this adds basic graphs and charts for your inventory, it
also includes minor changes to the dashboard graphs

first stab at #77 - add basic graphing engine and added a couple of graphs in the dashboard

fixes #70 - shows hosts in error state in the dashboard

added missing index page and added db indexs - ref #30

Fixes #30 - a very basic version for now - feature requests ARE WELCOMED