Windows compatibility #19

Hide WebP format and normalise option

Separate test runners for node and iojs

src/sharp.cc

@@ -8,6 +8,10 @@
 #include "resize.h"
 #include "utilities.h"
 
+#ifdef _WIN64
+#error Windows 64-bit currently unsupported - see https://github.com/lovell/sharp#windows
+#endif
+
 extern "C" void init(v8::Handle<v8::Object> target) {
   NanScope();
   vips_init("sharp");