Dropdown: blur when closing the menu
Revert "If there are no user contributions this month, just don't display the scores section"

This reverts commit 2afb96e44e6c0733fb4ef70ae71ec5e8e92a49a5.
Top scorers: don't cache queryset, but its evaluation
Fixed typo in docstring
Top scorers: don't filter out negative scores

Otherwise it would appear that contributors with negative scores didn't
even try to contribute to the translation.
Log used memory stats

Fix #237
Add more memory info (unreachable heap size and real memory size)