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Dev: Add SQL syntax highlighting
Dev: PHP output support for markdown, as it is used on the site in a few
places
Fix: DataTables/DataTables #281 - Invalidated DOM rows and hidden columns

- When invalidating a DOM row, DataTables wasn't taking into account the
  fact that the columns in the row might be hidden. This means that the
  array of data read is shortened by the number of hidden columns, and
  thus the data is corrupted.

- Fix is to read from the known cells if the row already exists