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This is part (hopefully all) of the fixes for #776.  The top-level
configure.ac configures googletest first and then googlemock.
With this changes it is possible to embed googletest into another
project that uses autoconf.  For an example (though it is WIP), see
the commits (and soon PR) referenced from google/protobuf#236.

Contributed by tk@giga.or.at.

Adds threading support (by Vlad Losev); updates the version number (by Zhanyong Wan); adds release notes for 1.5.0 (by Vlad Losev).

Adds threading support (by Miklos Fazekas, Vlad Losev, and Chandler Carruth); adds wide InitGoogleTest to gtest.def (by Vlad Losev); updates the version number (by Zhanyong Wan); updates the release notes for 1.5.0 (by Vlad Losev); removes scons scripts from the distribution (by Zhanyong Wan); adds the cmake build script to the distribution (by Zhanyong Wan); adds fused source files to the distribution (by Vlad Losev and Chandler Carruth).

Changes config_aux to build-aux to conform with the convention.  Simplifies the configuration commands in README.  By Chandler Carruth.

Enables the Python tests to run with 2.3 (necessary for testing on Mac OS X Tiger); also fixes gtest_output_test when built with xcode.