Update readme

Author: xtalax

README.md

@@ -13,14 +13,22 @@ prob = discretize(pdesys, discretization)
 ```
 Where dxs is a vector of pairs of parameters to the grid step in this dimension, i.e. `[x=>0.2, y=>0.1]`
 
+Note that the second argument to `MOLFiniteDifference` is optional, all parameters can be discretized if all boundary conditions are specified
+
 Currently supported grid types: `center_align` and `edge_align`
 
 center_align: naive grid, starting from lower boundary, ending on upper boundary with step of dx
 
 edge_align: offset grid, set halfway between the points that would be generated with center_align, with extra points at either end that are above and below the supremum and infimum by dx/2.
 This provides higher accuracy with neumann/robin boundary conditions.
 
-Currently boundary conditions defined in terms of derivatives at the boundary are unsupported.
+Currently boundary conditions defined in terms of derivatives at the boundary are unsupported above 1 discretized dimension. Periodic conditions are also unsupported.
+
+# Coming soon:
+- Arbitrary approximation order
+- Above mentioned unsupported boundary conditions supported
+- Staggered grids
+- More types of domain
 
 ## Full Example:
 ```