Checking number of attributes in tile4ms

[Mateusz Łoskot]

Hi,

Recently, I was fixing some GDAL issue reported by Bart
(http://bugzilla.remotesensing.org/show_bug.cgi?id=1144)
and I added tests of attributes scheman in input layers to ogrtindex
utility.

As discussed on Bugzilla
(http://bugzilla.remotesensing.org/show_bug.cgi?id=1144#c4)
it's recommended to check number of attributes, and if number is same,
schema of attributes.

I noticed that tile4ms utility does not compare number of attributes, so
I applied small fix. So, tile4ms handles differences in attributes of
input layers exactly in the same way as ogrtindex.

Is there any interest of such changes?
If there is, I can provide a patch.

Cheers
-- 
Mateusz Łoskot
http://mateusz.loskot.net