Changelog for 0.2.0

The following sections list the changes for 0.2.0.

Summary

Change #1: Add basic documentation

Add some basic documentation page which also includes build and installation instructions to
make clear how this project can be installed and used.

#1
Change #2: Pin xgo to golang 1.10 to avoid issues

There had been issues while using the latest xgo version, let's pin this tag to 1.10 to ensure the
binaries are properly build.

#2
Change #3: Update dependencies

Just make sure to update all the build dependencies to work with the latest versions available.

#3
Change #3: Lowercase datacenter label

To get the datacenter name labels normalized we are simply lowercasing the value from now on.

#3
Change #3: Timeout for metrics handler

We added an additional middleware to properly timeout requests to the metrics endpoint for
long running request.

#3
Change #3: Panic recover within handlers

To make sure panics are properly handled we added a middleware to recover properly from panics.

#3