Merge pull request #370 from spring-io/add-npm-shrinkwrap

Ensure reproducible JS builds
Migrate to JDK 8 Date/Time API

This commit begins the process of migrating to Java 8's Date and Time
API as described in issue #360.
Review pull request #372

 - Polish formatting and Javadoc in DateConverter
 - Rename DateConverterTest{=>s}
 - Use wildcards for static imports
 - Avoid wildcards for non-static imports
 - Optimize imports to ensure proper sorting of entries
Fix test regressions from 4e4b10f702
Migrate PostBuilder to JDK 8 Date/Time API

Issue #360
Fix failing test
Refactor commit  340a7a1 so that PostView uses only JDK 8 Date and Time API
Migrate SearchEntry and SearchEntryBuilder
Refactor DateConverter to use JDK 8 conversion methods