v0.2.0-rc1

In this release:

• Nanosecond precision for TTLs.
• TtlMap.Get now returns an additional bool like the original go map type.
• Introduced TtlMap.GetOrZero as replacement for the old Get method. This is not always clean to use with go's zero type values, but can be inlined.
• Most tests have been adapted to the new API (and all of them pass).

v0.1.0

This release is based on the TtlMap package by jftuga.

I made the TtlMap generic over its values for better type safety and performance. Examples and tests still need to be adapted.
I also removed the refresh functionality and will re-add it later in a different way.