Fix reconnection in Node 16 and above Pre-release

Abrupt server disconnects make it impossible for the client to reconnect, as reported in #16. This release fixes that problem.

Changes done by @jonathansamines in #17

Dependencies update

This release:

• updates Node compatibility from [4,10[ to [4,*[
• removes request as a dependency
• updates various development dependencies

Changes done by @jonathansamines in #15.

Update dependencies

Bumping request from 2.1.1 to 2.87.0 and node from * to >=4 <10 for tests.

Changes done by jonathansamines in #12.

Fix timestamp generation when both timestamp and callback are unset

This is a bugfix release for #10 which was fixed in PR #11 by @HughePaul.

When both the timestamp and the callback are unset when writing metrics, no timestamp is generated. This case is now properly handled.

Implement proper timestamp handling

In this release, we properly define what kind of timestamp should be fed when writing metrics with a fixed timestamp.

Until now, it was unclear whether one should use Date.now() or Math.floor(Date.now() / 1000). Having made it clear in the readme that the former option must be used, this ambiguity is now gone.

Add support for tagging

In Graphite 1.1.1 (21.12.17), tagging becomes available.

This release brings support for tagged writes. For information on how to actually write tagged metrics, see the readme.

Also, from this point on, semver will be used. Until proper tests have been put into place, version codes will be 0.y.z. When the software is reasonably stable, we will start from 1.0.0.