Update many Build.scala references

Removed as many references to `Build.scala` as I could find, and updated
them and the settings they were suggesting to update to `build.sbt`
format.

Fixes #1987
Extracted code snippets from Java body parsers documentation
Extracted code snippets from Java content negotiation documentation
Extracted code snippets from Java response documentation
Extracted code snippets from Java routing documentation
Extracted code snippets from Java session flash documentation
Fixed SSE event name regression

The SSE event name should be prefixed with the event: tag, not name:,
according to http://www.w3.org/TR/2009/WD-eventsource-20091029/.

This is a regression just on master, the code is fine on 2.2.x and
earlier.
Merge pull request #2224 from jroper/sse-event-name

Fixed SSE event name regression
Merge pull request #2218 from jroper/java-http-extract-docs

Java HTTP code snippets extraction
Fix play script indentation issue
Refactor Anorm Row trait
Merge pull request #2230 from cchantep/anorm-row

Refactor Anorm Row trait
Merge pull request #2226 from benmccann/script-spacing

Fix play script indentation issue
Merge pull request #1987 from jroper/1987-update-build-docs

Update documentation for build
Merge commit 'f02a5d79133c27878e83b55c6289d7ddc39a1998'

Conflicts:
	documentation/manual/javaGuide/main/tests/JavaTest.md