Prepare for 3.2.0 release.

Update changelog and version number.

Update Changelog and version.

Fix some issues with invalid hex-float literals.

When converting `0x` the converter would assert (or access out of
    boundary).
With `0x1.p1234556666FFFFF` the converter would overflow and not yield
the correct exponent.

Switch to relative includes.

Fixes google#91.

Fix typo in test.

Update Changelog and version number.

Upgrade version number.