Revert massive replacement of empty list creation sentences. The use of '[list]' instead of '{}' adds semantics that could be used for performance improvements in the future, such as using a different internal representation. There is already work in this direction, avoiding the generation of the string representation during comparison of empty strings (huge thanks to Stefan Sobernig for the pointer: https://core.tcl.tk/tcl/info/44527c632ed609c2).
Fixed a query for tasks (not displaying things correctly). Removed the code for deletion of the is_observer_p flag as it did not make much sense. Changed the behaviour of 'Pool Tasks' so they display all tasks where I'm participating. Mark all tasks where I'm not an observer with a green title
Made sure the projects portlet only shows projects you have a role in, unless you are in a community. Little bit of performacne tuning on the tasks portlet