Make transformations handles independent from canvas resolution
Fix bug with disappearing handles of Bline-tool when zoom
Fix bug with smooth move tool
Fix Duck constructor to avoid implicit instantiation of Duck
Fix warnings in state_stars.cpp
Use larger transformation widget
Skeleton layer is not an Experimental feature anymore.

Also, hide "Enable experimental features" option for now.
reFix-161 - Align rows of Params Panel and Timetrack Panel

- add a CellRendererText to TimeTrackView with same font attribute
to have same rows height.
161 - Align rows of Params Panel and Timetrack Panel - test

- add a CellRendererPixbuf at end of TimeTrackView.
161 - Align rows of Params Panel and Timetrack Panel - Progress7

WARNING THIS IS A TEMPORARY COMMIT
who have a reference to a hard linked ressource (1x16 alpha icon)

- Add initial support of alpha icon inside timetrack dock's treeview
- Add a gtk::drawingarea widget inside the timetrack dock's to align the time cursors
161 - Align rows of Params Panel and Timetrack Panel - Progress8

WARNING : HARD LINKED RESSOURCE

- Add utils_timetrack_align_icon.sif file
- Update icon procedure to include utils_timetrack_align_icon.sif
- Create icon stock icon for utils_timetrack_align_icon.sif
Fix161 - Align rows of Params Panel and Timetrack Panel - End

- Use the registred icon "utils_timetrack_align" in place of hard linked
Fix:The (orange) timecursor gets invisible behind primary graduation

In Widget_Timeslider::redraw, draw the cursor after the graduation