some purly cosmetic changes

adding semicolons for Q_DECLARE_METATYPE() and
Q_DECLARE_OPERATORS_FOR_FLAGS(), removing semicolons from Q_PROPERTY()
(QtCreator complains about them) and fixing a comment, reformatting for
alignment
move declaration nearer to definition
avoid use of a reserved keyword for a function name

even when it is inline
Merge pull request #900 from Jojo-Schmitz/plugin-framework

some cosmetic changes to the plugin framwork