My old surfaces module is actually broken at master branch, so I created a new branch called "sanguinariojoe-curvessurfaces" (following Jriegel criteria).

Some fixes and improvements have been done:

* Fixed ISO curves tool.
* Fixed Border curves tool.
* Hidden surface slice tool until is fixed.
* Hidden surfaces converter until is fixed.
* Added wires approximation by BSpline tool.
* Added Loft surfaces tool.
* Modified icons according to Draft/Part style.

Can someone take a look and merge on master if proceed?