lupdate is too "greedy" when collecting metadata from magic comments

Restrict how metadata can be specified for translations in source code so it doesn't get "greedy" and think that some comments are metadata when they are not. For example, the following line is considered to be metadata (even though its not)

B::B(QWidget *parent /*=0*/)

By restricting it to only have whitespace before the comment or something like that would make it easier to find the metadata and prevent it from running into problems.