Restructuring the geometry and pushers

The geometry and push structure has been reworked to allow eassy adding
new pushers.

Documentation not updated yet.

Baseline for merging Cartesian pushers into one.

runs/ALPHIE_Grid/inputIonization_0.10mA.json

@@ -8,7 +8,8 @@
 	"folder": "ionization_0.10mA"
   },
   "geometry": {
-    "type":     "2DCyl",
+    "dimension": 2,
+    "type":     "Cyl",
     "meshType": "gmsh2",
     "meshFile": "mesh.msh"
   },
@@ -58,10 +59,10 @@
     "temperature": 2500.0,
     "radius": 1.88e-10
   },
-  "case": {
+  "solver": {
     "tau":  [1.0e-9, 1.0e-11],
-    "time": 1.0e-6,
-    "pusher": ["2DCylCharged", "2DCylCharged"],
+    "finalTime": 1.0e-6,
+    "pusher": ["Electrostatic", "Electrostatic"],
     "WeightingScheme": "Volume",
     "EMSolver": "Electrostatic"
   },