Change default MemoryOutStream to be a std::ostringstream.

This changes restores the default behavior to that of UT++ 1.4.

It is accomplished by reintroducing the old UNITTEST_USE_CUSTOM_STREAMS
define, commented out, and surrounding the new define in an ifndef
block. It was done this way to preserve any unconventional users that
were specifying either flag in their build system, instead of in this
file.
Add install targets and install path customization.

This commit adds install() directives to the CMake file. By default,
headers will be installed to CMAKE_INSTALL_PREFIX/include/UnitTest++
and libUnitTest++.a will be installed to CMAKE_INSTALL_PREFIX/lib.

If the user defines UTPP_USE_PLUS_SIGN=OFF when generating, the ++
will be replaced with PP in both the library file name and the
include path.
Revert "Add install targets and install path customization."

This reverts commit 1fa77e11c6e3afa9c3f4f54c3c888bf5c713fed5.
Add install targets and install path customization.

This commit adds install() directives to the CMake file. By default,
headers will be installed to CMAKE_INSTALL_PREFIX/include/UnitTest++
and libUnitTest++.a will be installed to CMAKE_INSTALL_PREFIX/lib.

If the user defines UTPP_USE_PLUS_SIGN=OFF when generating, the ++
will be replaced with PP in both the library file name and the
include path.
Move unittestpp.h to src/UnitTestPP.h and add src/UnitTest++.h.

This is a 1.4 compatibility and consistency fix.
Move config.h to src/Config.h.

This is a 1.4 compatibility and consistency change.
Ensure all headers, including platform, are being installed.
Move src to UnitTest++ and move src/tests to tests.

CMakeLists was modified to support this, then include paths for the
test executable also had to be modified to include UnitTest++.
- Fixed include path in CMakeLists.txt
Merge pull request #34 from pjohnmeyer/version1.4CompatibilityFixes

Address multiple version 1.4 incompatibilities