Refactored signalprocessor tests and removed dependency to package RUnit.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rpnf@34 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Bugfix: Set warning level to 0 during plottxt, and restoring original value afterwards.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rpnf@35 edb9625f-4e0d-4859-8d74-9fd3b1da38cb