Fix post width & codeblocks

  I noticed that some url's were causing the posts to stretch over the
maximum device with.

  The code blocks were exhibiting similar behavior as well, and have
been adjusted to display well on all themes.

  I still need to fix the post form for handhelds, though it is not
as annoying as the other things fixed
Merge pull request #104 from kaernyk/master

Fix post width & codeblocks
remove default margin for table elements; fixes vichan-devel#95
Merge https://github.com/vichan-devel/vichan
Merge branch 'master' of https://github.com/ctrlcctrlv/8chan