sd:format-number() renamed to sd:format-string()

We will introduce a new function to include
thousand's separator and call that
sd:format-number().
New xpath function sd:format-number()

This function inserts thousands separators and
changes comma separators.
Br tags now allowed inside and outside of Value
Bugfix: table height when leading/rowsep != 0

When leading (which will be renamed one day) > 0
we did not calculate the remaining height
correctly.