Fixed discontinuous mortar bc:s as suggested by Christian. 

git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6745 04224531-1f84-46d8-96ce-875b9e37dce3
Added sign convention for the edge projector in case of conforming meshes created on-the-fly by a discontinuity. 


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6746 04224531-1f84-46d8-96ce-875b9e37dce3
Some comments to the mortar projector code.


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6747 04224531-1f84-46d8-96ce-875b9e37dce3
Added three new keywords related to stride projector.


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@6748 04224531-1f84-46d8-96ce-875b9e37dce3