Fix whitespace in init.js' updateProjects methods
Data views: only close current project when loaded from menu

Up to now the loading of a data view (the front page) caused any open
project to close. This commit changes this behavior to only close the
current project (and its windows) when the user opens a data view
through the data view menu (appearing when hovering the "Home" link).

Projects loaded with the help of a "URL to this view" link, now won't
get closed immediately anymore because of loading of the default data
view. This is related to isuse #537.
Make sure initial stacks get first loaded after login completion

The URL to a CATMAID instance can contain information about which stacks
to load at startup. Such a URL can be created with the help of tho "URL
to this view" link. The loading of these stacks, however, requires the
login procedure to have finished. This commit makes sure this is the
case by loading initial stacks in a callback method passed to the login
command. Without this, the handle_updateProjects() method would destroy
the newly created project right away. The callback is instead executed
*after* the potential deletion of an existing project. This is related
to issue #537.
Merge branch 'master' into orthoslices
fix navigation in zoom-levels < 0 (no integer rounding for x and y)
fixed selector tool to respect stack scale and orientation