Modifying SpringMobilityModel to make all nodes readjust after even one
node changes its position (previously only this node was adjusting itself)

SpringMobilityModel now updates positions based on internal (static) timer
diff --git a/examples/sprint-pops.weights b/examples/sprint-pops.weights
new file mode 100644
index 0000000..387a37f
--- /dev/null
+++ b/examples/sprint-pops.weights
@@ -0,0 +1,84 @@
+0 1 312
+2 3 10786
+1 4 222
+1 5 2500
+1 6 4000
+1 7 2500
+1 8 3860
+1 9 11769
+1 10 352
+1 11 3500
+12 13 2622
+14 15 500
+14 16 14192
+14 17 8909
+15 18 11747
+15 19 44530
+20 21 19775
+20 22 345
+23 24 5337
+25 26 2184
+27 28 645
+8 20 11409
+8 16 8282
+8 28 3000
+8 24 7735
+8 26 5500
+21 31 20741
+13 32 7552
+13 33 1500
+17 35 2091
+17 20 14409
+17 18 4337
+17 28 4000
+17 24 5735
+17 25 1315
+17 26 2500
+17 29 3282
+17 36 2478
+11 24 5096
+11 38 3235
+11 17 4360
+33 39 2000
+33 40 3000
+6 7 2500
+6 28 6860
+6 25 5176
+6 8 5860
+6 17 3860
+6 34 802
+6 11 5500
+39 42 699
+16 24 1547
+16 29 3000
+16 17 5282
+31 45 500
+31 46 268
+31 37 3375
+31 47 2708
+32 48 1712
+32 44 2329
+32 42 3352
+48 49 3201
+7 13 30890
+38 43 1643
+9 15 5500
+9 20 2500
+9 31 4735
+9 30 124
+9 17 13909
+9 19 42030
+5 32 28338
+5 8 2360
+5 7 2000
+18 23 5735
+40 48 2340
+40 49 2529
+24 38 2860
+24 31 9909
+24 45 10409
+24 50 92
+3 9 59812
+19 41 26190
+19 20 39530
+19 51 14125