Merge pull request #49 from alhardy/dev

fixed influxdb url formatting
Fixes #50 and #51

One static constructor requires the other constructor to finish creating
a cyclic loop. This is easily fixed by removing static constructor for
MetricsConfig and introducing a public static method. This method can be
called from Metric class.

Minimal changes, seems to work for me, but not sure about wider
implications. Please check and accept this pull request if all's good.
refactor how context timestamp is passed to reports
initial elasticsearch adapter support (WIP)
Merge remote-tracking branch 'omdr/master' into bugfix/disable-metrics
fix static constructor cyclic dependency. Fixes #50 & #51
add fields for hisograms and timers
update fluentassersions packages
update liblog
Merge branch 'feature/elasticsearch' into dev
bump version, push to nuget
Fix potential issue with NullTimer returning null context. Simplify null metrics.
upgrade xunit to v2
fix build script
bump version, push nuget
fix travis build
fix travis build
revert ti xunit 1.9 (2.0 fails on travis & appveyor)
bump version for Owin.Metrics and re-publish
fix path in create-nuget.bat for Nancy and Owin adapters