Added the option to use something other than thermal conductivity. (closes #3722)
 Add the same options to HeatConduction increase flexibility (closes
 #3722)
 Postprocessor now allows for other material names besides thermal conductivity. (closes #3722)
Merge pull request #3727 from micahjohnson150/flexible_homogenizationHX-3722

Flexible homogenization hx 3722
Merge commit '1dc18201a6ea9aee42d7307ecf5c9ee138975c2f'