Removed duplicate example

Removed duplicate code sample from the "Auto Plugins and plugin settings" section. This fixes issue #2996
Add migration notes about Pk deprecation (update related code samples)
Refactor SqlQuery case class as trait with companion object, so that it will be possible better check its creation. Update BatchSql, which was directly using SqlQuery at creation, replacing it by raw (string) statement, with SqlQuery created internally with checks.

```scala
import anorm.BatchSql

// Before
BatchSql(SqlQuery("SQL")) // No longer accepted (won't compile)

// Now
BatchSql("SQL")
// Simpler and safer, as SqlQuery is created&validated internally
```
Stop ClosableLazy throwing NPE when close called before get

Fixes #3024.
Merge pull request #3029 from cchantep/anorm-pkbk

Anorm Pk deprecation
Merge pull request #3030 from richdougherty/lazy-closable-npe

Stop ClosableLazy throwing NPE when close called before get
Typo: Unforseen -> Unforeseen
WsSSL exists in docs twice

Doesn't need to be in there the second time.
Merge pull request #3036 from vmunier/patch-1

Typo: Unforseen -> Unforeseen
Allow sending files with any status
Merge pull request #3042 from gmethvin/status_sendfile

Allow sending files with any status
frequency value typo
Merge pull request #3046 from sharpyfox/fix_akka_doc

Scala Documentation: Akka frequency value typo
Merge pull request #3027 from cchantep/anorm-sqlquery

Refactor SqlQuery case class as trait with companion object, so that it ...
Now looks for minified versions of assets for all asset reverse routes.