Several fixes to "make check-examples"

* fixed -pthread issue (ubuntu only?): Passing POSTLINKFLAGS to undocumented/libshogun/check.sh
** small changes to src/shogun/Makefile: Do not modify POSTLINKFLAGS from config

* fixed "make check-examples" (eclipse): now works without need for run "make install" first
** check-examples now passes library/include paths from source tree instead of target paths
** Added new makefile variable ABSCONFIGPATH with absolute config path