Limit 'inkscape:zoom' to 4 decimal places

Inkscape 0.91pre4 r13712 win64
Windows 7 SP1 x64

I've been noticing recently that sometimes really weird zoom levels are getting saved in some of my Inkscape files where the decimal places are sometimes going out 10+ places in the 'inkscape:zoom' line of the file after zooming in and out with my mouse.

To be honest, anything beyond 4 places is useless as there would be no way for anybody to see any difference and just wasting extra non-needed bytes in the saved file (maybe if you had 8 monitors all linked together it would be 'noticeable' then). For instance, if you need to set a zoom level of 1.25%, it would save in the file as 0.0125, which is 4 decimal places. That proves right there that Inkscape really doesn't need to save more than 4 places after the decimal.

I know, sure, it wouldn't save that many bytes (maybe 6 or more depending on the zoom level if it gets wacked out), but IMO, every extra eliminated byte counts in optimizing files. If eliminating just 6 bytes helps make a file fit into one block instead of two blocks on your hard drive, that's a big win in my book.