double-conversion

Double-conversion is a project that provides efficient binary-decimal and decimal-binary conversion routines for IEEE doubles. The code was extracted from the V8 JavaScript engine and refactored for easier use in other projects. The library includes documentation in string-to-double.h and double-to-string.h, with additional examples in test/cctest/test-conversions.cc. The library can be built with Scons or CMake, with the Makefile forwarding to Scons and providing a shortcut to run all tests. Scons can be used to install the static and shared library at the correct locations, with the option to change the target directory using DESTDIR. CMake can also be used, overwriting the existing Makefile and allowing for the compilation of shared libraries using BUILD_SHARED_LIBS=ON. Note that this disables static libraries and there is no way to build both libraries at the same time with CMake. BUILD_TESTING=ON can be used to build the test executable, followed by make and test/cctest/cctest.