With workspace thumbnails, we don't switch workspaces when dragging windows
between workspaces or adding new workspaces, so we also shouldn't switch
on launch.
* Add workspace parameters to shell_doc_system_open(),
shell_app_activate, shell_app_open_new_window()
* Pass a 'params' object when activating items in the overview with
two currently defined parameters: workspace and timestamp. (timestamp
is only implemented where it is easy and doesn't require interface
changes - using the global current timestamp for the shell is almost
always right or at least good enough.)
https://bugzilla.gnome.org/show_bug.cgi?id=640996
Brute force merge these two by essentially replacing St.TextureCache
with a (renamed) Shell.TextureCache.
One function was added for convenience, namely "st_texture_cache_load_file_simple".
St.TextureCache had a function to load a texture from a filename, and it
returned NULL on error but only half the callers actually checked this. This
function is better.
https://bugzilla.gnome.org/show_bug.cgi?id=607500
