Added missing 'blockquote' styles?

Hi,

Thanks for the Mou Solarized themes!  I noticed there was no styling for `<blockquote>` and added some in.

I hope I went about it all correctly (first time actually contributing to a github project so please forgive my newbness).

Cheers,

Jason

Signed-off-by: plmtr <w@plmtr.me>