Fix error in remove block w/ regex special chars

Previously, `remove` blocks that contained regular expression special
characters were throwing an error when instantiating a RegExp object to
match with. This commit escapes all regex special characters in the
offending block to ensure that a proper regular expression can be made.

Author: Jason Eberle

lib/blocktypes/remove.js

@@ -3,7 +3,8 @@
 module.exports = remove;
 
 function remove(content, block, blockLine, blockContent) {
+  var safeBlockLine = blockLine.replace(/[\-\[\]{}()*+?.,\\\^$|#\s]/g, '\\$&');
   // Replace blockLine with surrounding new line symbols (if present) with empty string
-  var linefeedStart = content.match(this.linefeed + blockLine) ? this.linefeed : '';
+  var linefeedStart = content.match(this.linefeed + safeBlockLine) ? this.linefeed : '';
   return content.split(linefeedStart + blockLine + this.linefeed).join('');
 }

test/expected/remove/remove_with_unescaped_regex_chars.html

@@ -0,0 +1,3 @@
+<!-- build:remove:testa -->
+ -[]{}()*+?.,\^$|#
+<!-- /build -->

test/fixtures/remove_with_unescaped_regex_chars.html

@@ -294,6 +294,23 @@ describe('remove_with_newline', function () {
   });
 });
 
+describe('remove_with_unescaped_regex_chars', function () {
+  it('should remove block also when the block contains unescaped regular expression special characters', function (done) {
+    htmlprocessor({
+        src: ['test/fixtures/remove_with_unescaped_regex_chars.html'],
+        dest: 'test/fixtures/remove/remove_with_unescaped_regex_chars.processed.html'
+    }, {
+        environment: 'testa'
+    });
+
+    var actual = utils.read('test/fixtures/remove/remove_with_unescaped_regex_chars.processed.html');
+    var expected = utils.read('test/expected/remove/remove_with_unescaped_regex_chars.html');
+    assert.equal(actual, expected);
+
+    done();
+  });
+});
+
 describe('inline', function () {
   it('should inline css and js for dist target', function (done) {
     htmlprocessor({