Modifications to detect holes in meshes,

began optimizing slices into continous polylines for export, and
overhang identification.
Merge branch 'master' of https://github.com/Pacmanfan/UVDLPSlicerController

Conflicts:
	UVDLP/Software/PC/UV_DLP_3dPrinter/UV_DLP_3D_Printer/GUI/frmMain.Designer.cs