Log Message:
Update to 2.16.6:
* Bugs fixed:
 161489 Make left/right arrows change focus between bookmarks...
 592883 Spin cell rendererer problem with double click
 478519 GtkTooltip segfaults on NULL gdk-display-current-tooltip.
 592003 Shift+click should always modify selection
 589195 gtktreeview.c warning
 588199 GtkTreeView rendering glitch while using a default sort...
 526149 GtkCellRendererAccel editing conflicts with mnemonics
 592901 Crash in JPEG pixbuf loader instead of error
 592461 preserve errno and use g_strerror
 589745 Apply message in GtkAssistant
 588943 set correct selection before emitting cursor-changed...
 592606 Activate the default button in a respose-request callback
 591526 Accelerator keys with <super> modifier also triggered...
 588958 Typo in startup-id window property
 580511 gdk_x11_atom_to_xatom_for_display translates GDK_NONE...
 564695 Pressing enter key in print to file "Name" box does not print
 528283 Problems when using PageUp & PageDown to navigate...
 534462 Focus issues in file chooser
 543310 set_enable_tree_lines doesn't work when a cellrenderer...

* Translation updates:
 Brazilian Portuguese
 Catalan (Valencian)
 Galician