add: pseudo_example.cpp, Grid.hpp | creating new API file and pseudo example

examples/pseudo_example.cpp

@@ -0,0 +1,25 @@
+
+// create a new grid 
+// dimension is implicitly determined by number of arguments
+// grid = new Grid(m=10, n=10)
+
+// array_x = array[]
+// array_y = array[]
+// grid.setAlpha_x(&array_x)
+// grid.setAlpha_y(&array_y)
+
+// float time
+// grid.setTimestep(time)
+
+// bc = new BoundaryCondition()
+// grid.setBoundaryCondition(bc)
+
+
+
+// create new simulation run
+// int iterations
+// bool csv = true
+// bool explicit = true
+// simulation = new Simulation(grid, iterations)
+// simulation.setSolver(BTCS, Thomas)
+// simulation.run()