imported 25 definitions from typescript-node-definitions

first batch: the easy pickings

- as per https://github.com/borisyankov/DefinitelyTyped/issues/115
- added DT headers (scraped creators from git history)
- added tests
- some modifications
- added CONTRIBUTORS.md for the substantial defs (>50 LOC)

sprintf/sprintf-tests.ts

@@ -0,0 +1,14 @@
+/// <reference path="sprintf.d.ts" />
+
+import sprintf = require('sprintf');
+
+var str: string;
+var num: number;
+
+sprintf.sprintf(str, str);
+sprintf.sprintf(str, str, num);
+sprintf.sprintf(str, num, str);
+
+sprintf.vsprintf(str, [str]);
+sprintf.vsprintf(str, [str, num]);
+sprintf.vsprintf(str, [num, str]);