GitLab

Renames EventListenrs to TestEventListeners (by Zhanyong Wan).
Fixes invalid characters in XML report (by Vlad Losev).
Refacotrs SConscript (by Vlad Losev).

Publishes the even listener API (by Vlad Losev); adds OS-indicating macros to simplify gtest code (by Zhanyong Wan).

Renames the TestPartResult type enums and adjusts the order of methods in the event listener interface (by Vlad Losev).

Renames the methods in the event listener API, and changes the order of *End events (by Vlad Losev).

Improves EXPECT_DEATH_IF_SUPPORTED to allow streaming of messages and enforcing the validity of arguments (by Vlad Losev); adds samples for the event listener API (by Vlad Losev); simplifies the tests using EXPECT_DEATH_IF_SUPPORTED (by Zhanyong Wan).