Made LIS linear solver return if it succeeded.

Fix AddTest

Fix dots in VTU file names

Added time measurement output

otherwise there are problems if some directory in the path contains dots in its
name.

no special behaviour if second path starts with dot
the old behaviour could cause problems with unix' hidden files or with parent
directories (..)

[PL] Update pre/postTimestep as in #1306.

See also "[PL] moved index computation to local assembler interface"
2d891b06 .

Fix surfaces lying in x-y-plane

Fix variable name _L to _length.

Added a wrapper for std::bind