fix tabbed literate code

lib/coffee-script/lexer.js

@@ -40,7 +40,7 @@
     };
 
     Lexer.prototype.clean = function(code) {
-      var line, lines;
+      var line, lines, match;
       if (code.charCodeAt(0) === BOM) {
         code = code.slice(1);
       }
@@ -55,8 +55,8 @@
           _results = [];
           for (_i = 0, _len = _ref2.length; _i < _len; _i++) {
             line = _ref2[_i];
-            if (LITERATE.test(line)) {
-              _results.push(line.substr(4));
+            if (match = LITERATE.exec(line)) {
+              _results.push(line.slice(match[0].length));
             } else {
               _results.push('# ' + line);
             }

src/lexer.coffee

@@ -65,15 +65,15 @@ exports.Lexer = class Lexer
 
   # Preprocess the code to remove leading and trailing whitespace, carriage
   # returns, etc. If we're lexing literate CoffeeScript, strip external Markdown
-  # by removing all lines that aren't indented by at least four spaces.
+  # by removing all lines that aren't indented by at least four spaces or a tab.
   clean: (code) ->
     code = code.slice(1) if code.charCodeAt(0) is BOM
     code = "\n#{code}" if WHITESPACE.test code
     code = code.replace(/\r/g, '').replace TRAILING_SPACES, ''
     if @literate
       lines = for line in code.split('\n')
-        if LITERATE.test line
-          line.substr(4)
+        if match = LITERATE.exec line
+          line[match[0].length..]
         else
           '# ' + line
       code = lines.join '\n'

test/literate.litcoffee

@@ -40,4 +40,9 @@ and unordered lists, are fine:
   
   * A
   
-  * List
+  * List
+
+Tabs work too:
+
+	test "tabbed code", ->
+		ok yes