Set monospace font so that carriage return character (for line continuation) is found.

Revert to modified keep-together rule for tables, as widow and orphan controls don't work quite as expected.

[SVN r51332]

tools/boostbook

@@ -1 +1 @@
-Subproject commit eac7e37f0a343c67fbb86c7cf29323c519d2d3fd
+Subproject commit 18f7121b7aaeec167700b0dbf017a1f2363472f7