WinRT: fixed bug whereby SDL would override an app's default orientation

WinRT apps can set a default, preferred orientation via a .appxmanifest file.
SDL was overriding this on app startup, and making the app use all possible
orientations (landscape and portrait).

Thanks to Eric Wing for the heads up on this!

visualtest/testsprite2_sample.parameters

@@ -0,0 +1,29 @@
+# parameter name, type, value range, required, categories
+--gldebug, boolean, [], false, []
+--info, enum, [all video modes render event], false, []
+--log, enum, [all error system audio video render input], false, []
+--display, integer, [1 5], false, []
+--fullscreen, boolean, [], false, []
+--fullscreen-desktop, boolean, [], false, []
+# --windows, integer, [1 5], false, [] # this option is not supported yet
+--title, enum, [vartest bartest footest], false, []
+--icon, enum, [icon.bmp], false, []
+--center, boolean, [], false, []
+--position, enum, [300,300], false, []
+--geometry, enum, [500x500], false, []
+--min-geometry, enum, [100x100], false, []
+--max-geometry, enum, [600x600 700x700], false, []
+--logical, enum, [500x500 550x450], false, []
+--scale, integer, [1 5], false, []
+--depth, integer, [1 5], false, []
+--refresh, integer, [1 5], false, []
+--vsync, boolean, [], false, []
+--noframe, boolean, [], false, []
+--resize, boolean, [], false, []
+--minimize, boolean, [], false, []
+--maximize, boolean, [], false, []
+--grab, boolean, [], false, [mouse]
+--blend, enum, [none blend add mod], false, []
+--cyclecolor, boolean, [], false, []
+--cyclealpha, boolean, [], false, []
+--iterations, integer, [10 100], false, []