Merge pull request #1 from morevnaproject/terms_rework_2

Fix paths for library_icon
Fine-tune type_vector_icon by making the line width smaller
Update tooltips of Group button of Layer Panel,from Group to Group Layer.
Merge branch 'terms_rework_2' of https://github.com/morevnaproject/synfig into morevnaproject-terms_rework_2

Conflicts:
	synfig-studio/images/type_vector_icon.sif
Revert internal name for library panel to fix connect bug.
Revert internal name for graph panel.
Revert the internal name for Set Panel.
Revert the internal name for parameters panel.
Revert the internal name for group layer to encapsulate
Correct the internal name of (layer) Set to the original one
Remove extra word "Spline" for some tool options.