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/rotate_by_quat.cpp

@@ -0,0 +1,55 @@
+// 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/.
+#include "rotate_by_quat.h"
+
+#include "quat_conjugate.h"
+#include "quat_mult.h"
+#include "normalize_quat.h"
+#include <cassert>
+
+template <typename Q_type>
+IGL_INLINE void igl::rotate_by_quat(
+  const Q_type *v,
+  const Q_type *q,
+  Q_type *out)
+{
+  // Quaternion form of v, copy data in v, (as a result out can be same pointer
+  // as v)
+  Q_type quat_v[4] = {v[0],v[1],v[2],0};
+
+  // normalize input 
+  Q_type normalized_q[4];
+
+#ifndef NDEBUG
+  bool normalized = 
+#endif
+  igl::normalize_quat<Q_type>(q,normalized_q);
+#ifndef NDEBUG
+  assert(normalized);
+#endif
+
+  // Conjugate of q
+  Q_type q_conj[4];
+  igl::quat_conjugate<Q_type>(normalized_q,q_conj);
+
+  // Rotate of vector v by quaternion q is:
+  // q*v*conj(q)
+  // Compute q*v
+  Q_type q_mult_quat_v[4];
+  igl::quat_mult<Q_type>(normalized_q,quat_v,q_mult_quat_v);
+  // Compute (q*v) * conj(q)
+  igl::quat_mult<Q_type>(q_mult_quat_v,q_conj,out);
+}
+
+#ifdef IGL_STATIC_LIBRARY
+// Explicit template instantiation
+// generated by autoexplicit.sh
+template void igl::rotate_by_quat<double>(double const*, double const*, double*);
+// generated by autoexplicit.sh
+template void igl::rotate_by_quat<float>(float const*, float const*, float*);
+#endif