Draft - Allow to export Drawing pages to DXF - fixes #1686

* Uses DXF algos of the Drawing module instead of the Draft dxf library
* Uses a DXF template with the same name as the SVG template, if existing
* Only Draft, Arch, Part and Annotation views are currently supported
* Drawing module's projectToDXF() now returns only a fragment instead of a full DXF file
Initial commit
Initial upload of files
Replaced PropertyLinkListEnum with PropertyLinkListInt
Replaced PropertyLinkListInt with PropertyIntegerList
remove unneeded files
Added <App/PropertyLinks.h> to FeatureFilling.h
Removed futher unneeded files
Fixed Compiler Error. Implementing BRepFill_Filling begun
Fixed Small Bug
Work in progress on BRepFill_Filling.
Implemented Border and arbitrary curve constraints order C0, G1 and G2
Fix bug in FeatureFilling and add initial FeatureSewing files
Bug fix
Small error fixed
Basic Filling algorithm working. Modified Sewing function
Removed unnecessary files
Removed additional file
Modified variable names to make more sense. Consolidated apply constraint subroutines. Removed extraneous printf statements
FeatureSewing incorporated. Todo: Object not displayed in tree