Bump version to 2.7.0-SNAPSHOT
Merge pull request #706 from caskdata/feature/bump-2.7.0-SNAPSHOT

Bump version to 2.7.0-SNAPSHOT
Spark Integration: Collect system metrics from Spark
Spark Integration: Added support for getting spark metrics from RunTimeStats
Spark Integration: Spark metrics unit test
Fix MetricsRequestParserTest by changing service id to u
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Spark Integration: add spark metric part parser
Added a test-case for spark in MetricsRequestParserTest
added missing break statement in switch case
Spark Integration: Added getMetricsCollector func which went missing in rebasing
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