Renamed GetReader to CreateReader

I feel this better documents what is actually happening (i.e. the reader
is not a cached value and is instead generated per call).

ssc/import resolver.cs

@@ -121,7 +121,7 @@ namespace arookas {
 			mStream.Dispose();
 		}
 
-		public TextReader GetReader() {
+		public TextReader CreateReader() {
 			return new StreamReader(mStream);
 		}
 	}

ssc/parser.cs

@@ -13,7 +13,7 @@ namespace arookas {
 		};
 
 		public sunNode Parse(sunScriptFile file) {
-			using (var input = file.GetReader()) {
+			using (var input = file.CreateReader()) {
 				try {
 					var parser = new __sunParser(input);
 					var node = parser.Parse();