Fix plugin structure

[scottux]

Why is there a tools folder in each plugin? This has never made sense to me. The source/release structure is a bit weird too, especially now that github offers a zip download of the repo and each plugin has its own tagging capability. The contents of the source folder are all we really need. Making zip files is easy to do programmatically.

[olegabr]

look here: https://github.com/qcubed/QDataTables/tree/master/tools
the tools directory contains not only standard make_package.* stuff, but plugin-specific utilities also.

Yes, plugins structure is outdated, but IMHO, we can really modernize it only with composer usage in mind, so, it waits for the v3.0