Allowed Java apps to configure CSRF error handler

It was possible to configure a CSRF error handler per action, but not if
you're using the global CSRFFilter.  This change makes that possible,
via supplying a csrf.error.handler configuration parameter with the
class name of the filter.
Issue #2668 fixed typo and issue #2690 minor rewrite of BuildingFromSource page.
Add fakeRequest(Call call) overload
Re-factored principally so that blocking operations can be managed. Thanks also to Nilanjan Raychaudhuri and Rich Dougherty for their contributions.

A self populating cache is now used in order to avoid any thundering herd issue.
Merge pull request #2724 from julienrf/java-fakerequest-call

play.test.Helpers.fakeRequest has no overload taking just a play.mvc.Call.
Merge pull request #2702 from huntc/async-asset-controller

Re-factor of the asset controller including caching
Merge pull request #2695 from kipsigman/master

Minor rewrite of BuildingFromSource.md and typo in documentation code
Updated doc w.r.t. the fixes related to https://github.com/playframework/playframework/issues/2662
Anorm Highlights
Reverse async Java test method changes

The synchronous API that was there previously is actually better for
most things. For other things using an integration test with a WS
client is fine. Reverses 6503338 and 8810a0b.
Issue #2687 [Docs] rewrite of Play WS docs.
Process multiple certificates into a keystore from a string.
Use Concurrent.unicast rather than broadcast for enumerating Java chunked responses

This change improved performance by 17% in one simple benchmark
Mute exhaustive match warnings when pattern matching Steps

This fixes warnings accidentally introduced in 27bf35e.
Use a Promise to avoid a race when attaching Chunks disconnect callbacks

I didn't actually see this race happening in practice, but I could see how it would be possible.
Merge pull request #2669 from jroper/csrf-filter-java-error

Allowed Java apps to configure CSRF error handler
Merge pull request #2713 from cchantep/anorm-hl23

Anorm Highlights
Applied the remainder of the factoring out of the spray-cache where the asset info cache is avoided when in development mode.
Merge pull request #2736 from huntc/nocache-when-dev

[trunk] assets caching prevents resources refreshing
Merge pull request #2623 from richdougherty/java-chunked-unicast

Use Concurrent.unicast for Java chunked responses