Snowplow Java Tracker v0.8.3

This release brings a sample project that sends events to a collector, fixes a few bugs, and updates building and testing for Java 11 support.

New content

• Add simple-console sample project (#191)

Bug fixes

• Close ResponseBody (#195)
• Make tracker exit cleanly (#187)

Under the hood

• Change some info statements to debug (#202)
• Change slf4j-simple to a test runtime dependency (#188)
• Use UTF-8 encoding in events (#181)
• Remove JDK7 and add OpenJDK8 in Travis build matrix (#205)
• Change sourceCompatibility and targetCompatibility to 1.8 (#204)
• Update Gradle to 5.0 (#203)
• Add Java 11 to Travis build matrix (#207)
• Fix README.md formatting (#190)