Convert Python types to proper Python type hierarchy.

Now much more inline with how CPython does types.
diff --git a/py/objfloat.c b/py/objfloat.c
index f151fe2..8fc925e 100644
--- a/py/objfloat.c
+++ b/py/objfloat.c
@@ -6,6 +6,7 @@
 #include "nlr.h"
 #include "misc.h"
 #include "mpconfig.h"
+#include "mpqstr.h"
 #include "obj.h"
 #include "runtime0.h"
 
@@ -18,12 +19,30 @@
 
 mp_obj_t mp_obj_new_float(mp_float_t value);
 
-void float_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in) {
+static void float_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in) {
     mp_obj_float_t *o = o_in;
     print(env, "%.8g", o->value);
 }
 
-mp_obj_t float_unary_op(int op, mp_obj_t o_in) {
+static mp_obj_t float_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *args) {
+    switch (n_args) {
+        case 0:
+            return mp_obj_new_float(0);
+
+        case 1:
+            // TODO allow string as arg and parse it
+            if (MP_OBJ_IS_TYPE(args[0], &float_type)) {
+                return args[0];
+            } else {
+                return mp_obj_new_float(mp_obj_get_float(args[0]));
+            }
+
+        default:
+            nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "float takes at most 1 argument, %d given", (void*)(machine_int_t)n_args));
+    }
+}
+
+static mp_obj_t float_unary_op(int op, mp_obj_t o_in) {
     mp_obj_float_t *o = o_in;
     switch (op) {
         case RT_UNARY_OP_NOT: if (o->value != 0) { return mp_const_true;} else { return mp_const_false; }
@@ -33,7 +52,7 @@
     }
 }
 
-mp_obj_t float_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
+static mp_obj_t float_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     if (MP_OBJ_IS_TYPE(rhs_in, &complex_type)) {
         return complex_type.binary_op(op, lhs_in, rhs_in);
     }
@@ -61,6 +80,7 @@
     { &mp_const_type },
     "float",
     float_print,
+    float_make_new, // make_new
     NULL, // call_n
     float_unary_op,
     float_binary_op,