#77 fixed import statements

changed the import statements for classes that were moved to the
cismet-commons-project. Furthermore removed the dependency to
cismet-gui-commons project. Also added a dependency to slf4j-log4j since
this dependency is no longer provided transitively through
cismet-gui-commons.
 #77 use HTTPAccessHandler without CredentialProvider

since the dependency to cismet-gui-commons is no longer present, we need
to use a HTTPAccessHandler without GUICredentialProvider in the
HTTPTunnelAction.
Merge branch 'feature/77-server-without-gui-commons' into dev