libvirt.tests: Add test module for timer management.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.tests: Test setting of timer's present to no.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.tests: Add stress relative cases for timer management.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.tests: Add windows support for timer management.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.tests: Use load_stress in utils_test for test.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.tests: Adjust testcases for timer test module.

  1.Block no_timer should not work under banned_timer because
    no timer is banned for test.
  2.In the four timers, only kvm-clock works.Other allowed timers
    are: pit, rtc and hypervclock
    (Leave it FAIL because RHEL6 manual does not point it out)

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #62 from yumingfei/timer

libvirt.tests: Add test module for timer management.