series: Show triangle for expandable test results
Test results are listed on a series view. Some of them are expandable if you click anywhere on their grey background. This is not obvious and it's not indicated in any way. This patch adds a triangle pointing down in the left corner to imply this expand/collapse behavior. The triangle starts pointing up when the section is expanded to indicate that it is collapsible now. Closes #35Signed-off-by:Arkadiusz Hiler <arkadiusz.hiler@intel.com>