Changed parameters for FV thermal models (now using Nw instead of N)

git-svn-id: https://thermopower.svn.sourceforge.net/svnroot/thermopower/trunk@192 80daafeb-7430-0410-91d5-8b30b0bbd841
Fixed bug in replaceable heat transfer models (modifiers should go on constraining class)

git-svn-id: https://thermopower.svn.sourceforge.net/svnroot/thermopower/trunk@193 80daafeb-7430-0410-91d5-8b30b0bbd841
Added missing connect statement for heat transfer model
Removed old commented-out code

git-svn-id: https://thermopower.svn.sourceforge.net/svnroot/thermopower/trunk@194 80daafeb-7430-0410-91d5-8b30b0bbd841