[#6] Using dependency.yml to get spring libs

[sliverc]

Currently it is not possible to overwrite the version of spring when depending from the spring module.

This pull request adds a dependency.yml so spring is part of the dependency management. Furthermore does it update spring to the newest spring version.

Note that all optional dependencies are excluded.

See also #6

[tmbrggmn]

Seems like a good addition; would love to see this integrated!

[ni-ka]

+1
As a workaround, you can simply delete the spring libraries from [play]/modules/spring/lib. I then used maven to fetch spring - mainly because I had a pom with other dependencies already.
However this behavior should be configurable.

[ndeverge]

+1
I'd love to see that too !

[scott-phillips]

+1
This would make life much simpler.

[pepite]

Included thanks