Replace CSparse linear solver by Eigen (#119)

Author: alxbilger

examples/AdaptiveBeamController.scn

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <Node name="root" gravity="0 -9.81 0" dt="0.01" >
 	<RequiredPlugin name="Sofa.Component.Constraint.Projective"/> <!-- Needed to use components [FixedConstraint] -->
-	<RequiredPlugin name="Sofa.Component.LinearSolver.Direct"/> <!-- Needed to use components [SparseLUSolver] -->
+	<RequiredPlugin name="Sofa.Component.LinearSolver.Direct"/> <!-- Needed to use components [EigenSparseLU] -->
 	<RequiredPlugin name="Sofa.Component.ODESolver.Backward"/> <!-- Needed to use components [EulerImplicitSolver] -->
 	<RequiredPlugin name="Sofa.Component.StateContainer"/> <!-- Needed to use components [MechanicalObject] -->
 	<RequiredPlugin name="Sofa.Component.Topology.Container.Constant"/> <!-- Needed to use components [MeshTopology] -->
@@ -11,7 +11,7 @@
 
 	<Node name="AdaptiveBeam1">
 		<EulerImplicitSolver rayleighStiffness="0" rayleighMass="0" printLog="false" />
-		<SparseLUSolver template="CompressedRowSparseMatrixMat3x3d"/>
+		<EigenSparseLU template="CompressedRowSparseMatrixMat3x3d"/>
 		<MechanicalObject template="Rigid3d" name="DOFs" position="0 0 0 0 0 0 1  0.5 0 0 0 0 0 1  1 0 0 0 0 0 1  1.5 0 0 0 0 0 1  2 0 0 0 0 0 1  2.5 0 0 0 0 0 1  3 0 0 0 0 0 1"/> 
 		<MeshTopology name="lines" lines="0 1 1 2 2 3 3 4 4 5 5 6" /> 
 		<FixedConstraint name="FixedConstraint" indices="0" />
@@ -29,7 +29,7 @@
 
 	<Node name="AdaptiveBeam2">
 		<EulerImplicitSolver rayleighStiffness="0" rayleighMass="0" printLog="false" />
-		<SparseLUSolver template="CompressedRowSparseMatrixMat3x3d"/>
+		<EigenSparseLU template="CompressedRowSparseMatrixMat3x3d"/>
 		<MeshTopology name="lines" lines="0 1 1 2 2 3" /> 
 		<MechanicalObject template="Rigid3d" name="DOFs" position="0 0 2 0 0 0 1  1 0 2 0 0 0 1  2 0 2 0 0 0 1  3 0 2 0 0 0 1"/> 
 		<BeamInterpolation name="BeamInterpolation2" radius="0.1" />