Switch from mercurial to git.

This commit imports mercurial revision c8b89fb5c5b4.
Update comment: we don't allow NaN/(-)Infinity when invoking DoubleToAscii.
Update comment to give hints for computing the output size.
Added Changelog file.
Merge single-branch from mercurial (9ff9d9e904c9) into master.
DoubleToAscii's input must not be special.

In SHORTEST_SINGLE this restriction also applies to static_cast<float>(v).
Update Changelog.
Add .gitignore and use ASSERT instead of assert.

Both changes from Martin Olsson.
Fixes issue 21 and 22.
Remove double parenthesis and add 'LIBS' to SConstruct file.
Null terminate exponent buffer.

Fixes issue 26.
Support more architectures.

Patch from Mike Homney (Mozilla Foundation).
Merge branch 'fix_null_termination'
Update Changelog.
Mark StringToDoubleConverter functions as 'const'.
Merge branch 'make_methods_const'