v2.1.0: Support both Marathon 1.6 and marathon 1.8+

Merge pull request #25 from criteo/fix-marathon-1.8-exports

Fix export of Gauges in Marathon newer versions

v2.0.0: Merge pull request #18 from criteo-forks/gauge

Support for Marathon 1.5+

v1.5.0

Adds

• app_version label to marathon app metrics

Fixes

• #8 Avoid race in accessing counters and gauges.

v1.5.0-RC1

Added:

• app_version label to marathon app metrics

v1.4.3

• Fixes #6

v1.4.2

v1.4.2

v1.4.1

Added gauge:

• avg_uptime (corresponds to taskStats.startedAfterLastScaling.stats.lifeTime.averageSeconds)

v1.4.0

Added gauges:

• cpus
• gpus
• mem_in_mb
• disk_in_mb

v1.3.2

Version 1.3.2