Refactor build system to use waf. Waf is better at handling dependency paths which I need for IDL support

bin/pidl/TODO

@@ -0,0 +1,44 @@
+- warn when union instances don't have a discriminant
+
+- true multiple dimension array / strings in arrays support
+
+- compatibility mode for generating MIDL-readable data:
+ - strip out pidl-specific properties
+
+- make bitmap an optional attribute on enum
+- support nested elements
+- support typedefs properly (e.g. allow "typedef void **bla;")
+- make typedefs generate real typedefs
+- improve represent_as(): allow it to be used for arrays and other complex 
+  types
+
+- --explain-ndr option that dumps out parse tree ?
+
+- seperate tables for NDR and DCE/RPC
+ - maybe no tables for NDR at all? we only need them for ndrdump 
+   and that can use dlsym()
+
+- allow data structures outside of interfaces
+
+- mem_ctx in the interface rather than as struct ndr member.
+
+- real typelibs
+
+- fix [in,out] handling and allocation for samba3:
+ - add inout
+ - make NULL to mean "allocate me"
+ - remove NDR_AUTO_REF_ALLOC flag
+
+- automatic test generator based on IDL pointer types
+
+- support converting structs to tuples in Python rather than objects
+- convert structs with a single mattering member to that member directly, e.g.:
+  struct bar {
+    int size;
+	[size_is(size)] uint32 *array;
+  };
+
+  should be converted to an array of uint32's
+
+- python: fill in size members automatically in some places if the struct isn't being returned
+  (so we don't have to cope with the array growing)