Consistent folder name casing

Source commit: 9f60d1931e9f6accd87fa8d6f652e280b7faa963

source/Putty.cbproj

@@ -326,7 +326,7 @@
 			<BuildOrder>83</BuildOrder>
 			<BuildOrder>3</BuildOrder>
 		</CppCompile>
-		<CppCompile Include="putty\WINDOWS\windefs.c">
+		<CppCompile Include="putty\windows\windefs.c">
 			<BuildOrder>83</BuildOrder>
 		</CppCompile>
 		<CppCompile Include="putty\windows\wingss.c">
@@ -343,7 +343,7 @@
 			<BuildOrder>92</BuildOrder>
 			<BuildOrder>14</BuildOrder>
 		</CppCompile>
-		<CppCompile Include="putty\WINDOWS\winmiscs.c">
+		<CppCompile Include="putty\windows\winmiscs.c">
 			<BuildOrder>76</BuildOrder>
 		</CppCompile>
 		<CppCompile Include="putty\windows\winnet.c">