(CDAP-512) Service system metrics
Merge branch 'develop' of github.com:caskdata/cdap into feature/CDAP-512-DefaultServiceMetrics
Addressing comments
Revert metricsRequestParser
Addressing comments
Merge branch 'develop' of github.com:caskdata/cdap into feature/CDAP-512-DefaultServiceMetrics

Conflicts:
	cdap-unit-test/src/test/java/co/cask/cdap/test/app/TestFrameworkTest.java
Fix tesT
Fix logging comment
Merge pull request #699 from caskdata/feature/CDAP-512-DefaultServiceMetrics

Feature/cdap 512 default service metrics
CDAP-713: Updated SparkPageRank archetype according to migration from procedures to services.
CDAP-538: Updated scripts to use new services; Minor docs update.
Merge pull request #700 from caskdata/feature/file-separate-module

Feature/file separate module
CDAP-538: Updated docs.
Merge remote-tracking branch 'upstream/release/2.6.0' into CDAP-713/SparkPageRank-example-archetype-2.6.0
CDAP-713: Updated docs.
Merge pull request #704 from cybervisiontech/CDAP-538-spark-page-rank-app-2.6.0

CDAP-538: Updated scripts to use new services; Minor docs update.
Merge pull request #703 from cybervisiontech/CDAP-713/SparkPageRank-example-archetype-2.6.0

CDAP-713: Updated SparkPageRank archetype according to migration to services.
wip: docs metrics start
metrics documentation changes, changed history endpoint to runs, gauge example, querying by run-id
make all implementations of getDataSet() throw DataSetInstantiationException