hide robots.txt filr via .gitignore
fix image attribute mispelling on "eloquent javascript" post (see msg)

the image width attribute for the image in the "eloquent javascript" post is completly mispelled (it's spelled widyh"250" and it should read width="250"). This keeps the 'grunt:htmlmin' task from minifying all the HTML. fix the spelling error and run the task again to confirm that all is working.