Building igl statically and moving to the dep scripts

Fixing dep build script on Windows and removing some warnings.

Use bundled igl by default.

Not building with the dependency scripts if not explicitly stated. This way, it will stay in
Fix the libigl patch to include C source files in header only mode.

src/libigl/igl/opengl2/gl.h

@@ -0,0 +1,44 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+//
+// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public License
+// v. 2.0. If a copy of the MPL was not distributed with this file, You can
+// obtain one at http://mozilla.org/MPL/2.0/.
+#ifndef IGL_OPENGL2_GL_H
+#define IGL_OPENGL2_GL_H
+
+#ifdef IGL_OPENGL_GL_H
+#  error "igl/opengl/gl.h already included"
+#endif
+
+// Always use this:
+//     #include "gl.h"
+// Instead of:
+//     #include <OpenGL/gl.h>
+// or
+//     #include <GL/gl.h>
+//
+
+// For now this includes glu, glew and glext (perhaps these should be
+// separated)
+#ifdef _WIN32
+#    define NOMINMAX
+#    include <Windows.h>
+#    undef DrawText
+#    undef NOMINMAX
+#endif
+
+#ifndef __APPLE__
+#  define GLEW_STATIC
+#  include <GL/glew.h>
+#endif
+
+#ifdef __APPLE__
+#  include <OpenGL/gl.h>
+#  define __gl_h_ /* Prevent inclusion of the old gl.h */
+#else
+#  include <GL/gl.h>
+#endif
+
+#endif