When setting a Hebrew locale, Writer by default starts all documents as RTL
(which is good), and Calc starts all sheets as RTL.

However, all the cells in the sheet are set as RTL, and the setting is kept even
when the sheet direction is changed to LTR.

This is very annoying when working with lots of numeral content (which is always
LTR)- even if the user wants the sheet itself to be RTL, most of the content of
the sheet is still LTR (this can be seen very clearly in Hebrew excel files
loaded to the web- most of them have RTL sheets, where most of the content is LTR).

At the moment, the user has two not-so-good options:
* Leave the locale setting in OOo as Hebrew (to benefit from RTL pages in writer
and other niceties), but for each and every sheet for every file, click once to
select all cells, and click another time to change them all to LTR (regardless
if the user want the general sheet direction to be LTR or RTL- changing sheet
direction does not change the direction of the cell, which *is* the correct
action). This really adds up over time.

* Don't use a RTL locale, and then loose default RTL pages in Writer, default
RTL sheets in calc and other small issue.

IMO, we should either default cell direction to LTR (as most content is numeral,
which is always LTR), or give the user the option of choosing default cell
direction.