Add Kossel Mini printer definition

Added Kossel Mini Printer definition. It is the first delta printer working on Cura; I tested it before uploading this .def.json file and its accompanying .stl file. Works but there is some mysterious padding at the sides of the "square" (?) heated bed that disallow the part but these are not areas I configured. I approximated the round shape of the bed with 8 polygons for disallowed areas. However the square checkerboard pattern appears on top of it and it is kind of annoying, hope someone would fix this.

resources/definitions/kossel_mini.def.json

@@ -0,0 +1,67 @@
+{
+    "id": "kossel_mini",
+    "version": 2,
+    "name": "Kossel Mini",
+    "inherits": "fdmprinter",
+    "metadata": {
+        "visible": true,
+        "author": "Claudio Sampaio (Patola)",
+        "manufacturer": "Other",
+        "category": "Other",
+        "file_formats": "text/x-gcode",
+        "icon": "icon_ultimaker2",
+        "platform": "kossel_platform.stl"
+    },
+
+    "overrides": {
+        "machine_heated_bed": {
+            "default_value": true
+        },
+        "machine_width": {
+            "default_value": 170
+        },
+        "machine_height": {
+            "default_value": 200
+        },
+        "machine_depth": {
+            "default_value": 170
+        },
+        "machine_center_is_zero": {
+            "default_value": true
+        },
+        "machine_nozzle_size": {
+            "default_value": 0.4
+        },
+        "material_diameter": {
+            "default_value": 1.75
+        },
+        "machine_nozzle_heat_up_speed": {
+            "default_value": 2
+        },
+        "machine_nozzle_cool_down_speed": {
+            "default_value": 2
+        },
+        "machine_gcode_flavor": {
+            "default_value": "RepRap (Marlin/Sprinter)"
+        },
+        "machine_start_gcode": {
+            "default_value": "G21 ;metric values\nG90 ;absolute positioning\nM82 ;set extruder to absolute mode\nM107 ;start with the fan off\nG28 ;Home all axes (max endstops)\nG1 Z15.0 F9000 ;move the platform down 15mm\nG92 E0 ;zero the extruded length\nG1 F200 E3 ;extrude 3mm of feed stock\nG92 E0 ;zero the extruded length again\nG1 F9000\n;Put printing message on LCD screen\nM117 Printing..."
+        },
+        "machine_end_gcode": {
+            "default_value": "M104 S0 ;extruder heater off\nM140 S0 ;heated bed heater off (if you have it)\nG91 ;relative positioning\nG1 E-1 F300  ;retract the filament a bit before lifting the nozzle, to release some of the pressure\nG28 ;Home all axes (max endstops)\nM84 ;steppers off\nG90 ;absolute positioning"
+        },
+        "machine_disallowed_areas": {
+            "default_value": [
+                [[-34,  -85], [ -85,  -85], [-70,  -70]],
+		[[-85, -85], [-85, -34], [-70, -70]],
+                [[34,  -85], [ 85,  -85], [70,  -70]],
+		[[85, -85], [85, -34], [70, -70]],
+                [[-34,  85], [ -85,  85], [-70,  70]],
+		[[-85, 85], [-85, 34], [-70, 70]],
+                [[34,  85], [ 85,  85], [70,  70]],
+		[[85, 85], [85, 34], [70, 70]]
+            ]
+        }
+
+    }
+}