[NEW] Any real valued keyword may be normalized by area (or volume) by giving keyword 'keyword normalize by area' (or volume) resulting to the value of 'keyword' being divided by the area (volume) at the time of calling. The area should be the operator for BCs and for other field (material, body, body force) the volume should apply. Current limitation is that there can only be one mesh. The features is totally generic but has a small additional cost as there is an additional multiplication by a constant. 

At the same time some minor reconstructing of the ListGet operations such that the Constant_Procedure case is now treated as a separate case. This removed one check from ListGet operations for real constants thereby compensating a little for the additional multiplication. 


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@7023 04224531-1f84-46d8-96ce-875b9e37dce3