Module name validation

This pull request depends on both PR https://github.com/ceylon/ceylon-ide-intellij/pull/49 (which seems to be actually included in this PR currently - maybe it will not once the first PR gets merged?) and PR https://github.com/ceylon/ceylon-ide-common/pull/2 being merged first.

It fixes issue #47 by using the ide-common new ``NameValidator`` class to validate module names.