Spring-Scala 2.11

Scala 2.11 has been released half of year from now. And majority of projects now supports both versions of Scala 2.10 and 2.11.

Here is the list what this pull request covers:

* change imports of scala.reflect.BeanProperty into scala.beans.BeanProperty, as it is deprecated in Scala 2.10 and was removed in Scala 2.11
* upgrade minimum amount of libraries in order to make it compiled with Scala 2.11
* upgrade Gradle to version 1.12, which has [breaking change](http://www.gradle.org/docs/1.12/release-notes#incremental-scala-compilation), which allows to compile with Scala 2.11 `compiler-interface` (it doesn't work for Gradle 1.11)
* all tests are passing

Here is the list what this pull request _does not_ cover:
* there is lot of deprecation messages in codebase; all of those are fixed (except `DelayedInit` though it's more likely architecture's change), and all tests are passing; but those changes are not included into this pull request, unless you tell me otherwise
* not all libraries are upgraded to the latest versions
* there is no support of cross-build for both `2.10` and `2.11` versions

If any of those are necessary, I can add it to this pull request.

Any feedbacks are appreciated. Thanks in advance.

Cheers, Nick.