fix FileProcessor.prototype.replaceBlocks bug

In FileProcessor.prototype.replaceBlocks,the replacement contains$&(special character),String.replace isn't work.
the version seems unusable:

    var replacement = 'foo$&foo$&foo', content = 'foo\nbar\nbaz\n';

    replacement = replacement.replace(/\$/g, "\\$");
    console.log(replacement);
    // expect:foo\$&foo\$&foo
    // actual:foo\$&foo\$&foo

    content = content.replace('bar\nbaz', replacement);
    console.log(content);
    // expect:foo\nfoo\$&foo\$&foo\n
    // actual:foo\nfoo\bar\nbazfoo\bar\nbazfoo\n