Merge linedTable and generalTable CSS styles

[PaulMorris]

In PR #1049 we introduced a linedTable CSS class to draw lines between table rows of certain tables and increase the line-height in table cells a bit. This let us only affect those tables we were working on in that PR.

But eventually it probably makes sense to merge the linedTable styles into the generalTable class styles, so all tables have those styles for consistency and to simplify things. We didn't do this at the time because we'd want to check how those new styles would affect the many generalTable instances, and there wasn't bandwidth to do that.