POM Element for Source File Encoding

Currently, the character encoding for source files needs to be configured individually for each and every plugin that processes source files.

Life would become easier if there was a dedicated POM element like ${project.sourceEncoding} which could be use to specify the encoding once per entire project.

Please see [0] for the related thread from the mailing list, and [1] for some further descriptions: proposed element is now ${project.build.sourceEncoding}