Move parts of solver into its own package. Closes #19

Reviewed-on: #22

controller/types.go

@@ -0,0 +1,18 @@
+package controller
+
+type Controller struct {
+	Blocks    []int
+	Row1      string
+	Row2      string
+	Row3      string
+	Row4      string
+	Row5      string
+	Row6      string
+	Row7      string
+	Row8      string
+	Row9      string
+	Solutions []string
+	NumCPUs   int
+	Split     int
+	Part      int
+}