Updated to use MeshGraphIO from Nektar++

Included MeshGraphIO.h from new version of Nektar++ and changed calls from MeshGraph::Read to MeshGraphIO::Read.

meshes/square-quads.msh

+$MeshFormat
+4.1 0 8
+$EndMeshFormat
+$Entities
+4 4 1 0
+1 0 0 0 0 
+2 1 0 0 0 
+3 0 1 0 0 
+4 1 1 0 0 
+1 0 0 0 1 0 0 1 1 2 1 -2 
+2 0 1 0 1 1 0 1 3 2 3 -4 
+3 0 0 0 0 1 0 1 4 2 1 -3 
+4 1 0 0 1 1 0 1 2 2 2 -4 
+5 0 0 0 1 1 0 1 0 4 1 4 -2 -3 
+$EndEntities
+$Nodes
+9 25 1 25
+0 1 0 1
+1
+0 0 0
+0 2 0 1
+2
+1 0 0
+0 3 0 1
+3
+0 1 0
+0 4 0 1
+4
+1 1 0
+1 1 0 3
+5
+6
+7
+0.25 0 0
+0.5 0 0
+0.75 0 0
+1 2 0 3
+8
+9
+10
+0.25 1 0
+0.5 1 0
+0.75 1 0
+1 3 0 3
+11
+12
+13
+0 0.25 0
+0 0.5 0
+0 0.75 0
+1 4 0 3
+14
+15
+16
+1 0.25 0
+1 0.5 0
+1 0.75 0
+2 5 0 9
+17
+18
+19
+20
+21
+22
+23
+24
+25
+0.25 0.25 0
+0.25 0.5 0
+0.25 0.75 0
+0.5 0.25 0
+0.5 0.5 0
+0.5 0.75 0
+0.75 0.25 0
+0.75 0.5 0
+0.75 0.75 0
+$EndNodes
+$Elements
+5 32 1 32
+1 1 1 4
+1 1 5 
+2 5 6 
+3 6 7 
+4 7 2 
+1 2 1 4
+5 3 8 
+6 8 9 
+7 9 10 
+8 10 4 
+1 3 1 4
+9 1 11 
+10 11 12 
+11 12 13 
+12 13 3 
+1 4 1 4
+13 2 14 
+14 14 15 
+15 15 16 
+16 16 4 
+2 5 3 16
+17 1 5 17 11 
+18 11 17 18 12 
+19 12 18 19 13 
+20 13 19 8 3 
+21 5 6 20 17 
+22 17 20 21 18 
+23 18 21 22 19 
+24 19 22 9 8 
+25 6 7 23 20 
+26 20 23 24 21 
+27 21 24 25 22 
+28 22 25 10 9 
+29 7 2 14 23 
+30 23 14 15 24 
+31 24 15 16 25 
+32 25 16 4 10 
+$EndElements