fix build failing in travis.

start xvfb in travis-ci

fix build process for travis

fix tests for cunit v2.1

fix some documents and function name.

change X display number in run-test to avoid conflict with .travis.yml

add binary running test

fix X11 options (--display etc.) can be used

fix config_parser_test to fail rarely

fix to fail distclean

modify run-test.sh not using stderr output of idletimer

set travis-ci starting X11 server (xvfb)

set travis-ci uploading artifacts

fix package names of libgtk-* in INSTALL.md

fix libgtk-2 package name for travis ci