Allow version 2.1 to use linenos, start and mark in code block

This is only for people who wants "start, mark" in the code block in 2.1.

This is actually a quick hack getting from version 2.5's plugins

I tried to setup using branch 2.5 on my Windows machine but failed.

After sometime I give up as it looks like most of the development effort are now in 3.0, therefore I decided to merge only the corresponding plugins in 2.5 to 2.1, then I find that the default theme doesn't support for line number. So I merge those theme as well.

Reference I used include:
https://groups.google.com/d/msg/octopress/y1IlHmFYydQ/MCSBrDrL1XIJ