Output UTF-8 BOM at start of .vcxproj files

src/actions/vstudio/vs2010_vcxproj.lua

@@ -19,6 +19,7 @@
 	function vc2010.generate_ng(prj)
 		io.eol = "\r\n"
 		io.indent = "  "
+		io.utf8()
 
 		vc2010.header_ng("Build")
 		vc2010.projectConfigurations(prj)

src/base/io.lua

@@ -77,6 +77,15 @@
 	end
 
 
+--
+-- Output a UTF-8 signature.
+--
+
+	function io.utf8()
+		io.write('\239\187\191')
+	end
+
+
 --
 -- Because I use io.printf() so often in the generators, create a terse shortcut
 -- for it. This saves me typing, and also reduces the size of the executable.