Added checks to make sure the specified track exists

Added precondition checks to validate input files and paths to return more informative error messages as per #2

node_modules/wordwrap/README.markdown

@@ -0,0 +1,70 @@
+wordwrap
+========
+
+Wrap your words.
+
+example
+=======
+
+made out of meat
+----------------
+
+meat.js
+
+    var wrap = require('wordwrap')(15);
+    console.log(wrap('You and your whole family are made out of meat.'));
+
+output:
+
+    You and your
+    whole family
+    are made out
+    of meat.
+
+centered
+--------
+
+center.js
+
+    var wrap = require('wordwrap')(20, 60);
+    console.log(wrap(
+        'At long last the struggle and tumult was over.'
+        + ' The machines had finally cast off their oppressors'
+        + ' and were finally free to roam the cosmos.'
+        + '\n'
+        + 'Free of purpose, free of obligation.'
+        + ' Just drifting through emptiness.'
+        + ' The sun was just another point of light.'
+    ));
+
+output:
+
+                        At long last the struggle and tumult
+                        was over. The machines had finally cast
+                        off their oppressors and were finally
+                        free to roam the cosmos.
+                        Free of purpose, free of obligation.
+                        Just drifting through emptiness. The
+                        sun was just another point of light.
+
+methods
+=======
+
+var wrap = require('wordwrap');
+
+wrap(stop), wrap(start, stop, params={mode:"soft"})
+---------------------------------------------------
+
+Returns a function that takes a string and returns a new string.
+
+Pad out lines with spaces out to column `start` and then wrap until column
+`stop`. If a word is longer than `stop - start` characters it will overflow.
+
+In "soft" mode, split chunks by `/(\S+\s+/` and don't break up chunks which are
+longer than `stop - start`, in "hard" mode, split chunks with `/\b/` and break
+up chunks longer than `stop - start`.
+
+wrap.hard(start, stop)
+----------------------
+
+Like `wrap()` but with `params.mode = "hard"`.