Merge pull request #15 from igor-borisov/master

Fixed bugs, new details window added
Get validation-api version
cache for "fetch versions"
license information added (VersionStorage.java)
Merge pull request #16 from maxim-minin/master

Get validation-api version, cache for "fetch version".
Merge branch 'master' of https://github.com/arcusys/liferay-vaadin-plugin