mapcache_seed ignores x-axis constraints (perhaps only if the X coordinate is wrapped around the world?)

[ramayer]

With the rectangle specified below (which came from openlayers's javascript), mapcache_seed always seems to start with "x1" and go all the way up to the tile I wanted, as shown here.

This mapcache_seed was built against today's master branch in github.

gisadmin@mapcache-02:~/mapcache/build$ cmake ..
gisadmin@mapcache-02:~/mapcache/build$ make
gisadmin@mapcache-02:~/mapcache/build$ sudo -u  www-data  ./util/mapcache_seed -P 100 -n 4 -c /etc/mapcache/mapcache.xml -t school_zones -z 8,8 -f -e -52428554,3792696,-52428553.999999,3792696.000001 -v
seeded 25 tiles, now at z8 x15 y150                                                            
seeded 250 tiles, now at z8 x50 y150                                                           
seeded 450 tiles, now at z8 x90 y150                                                           
seeded 650 tiles, now at z8 x135 y150                                                          
seeded 925 tiles, now at z8 x190 y150                                                          
seeded 1275 tiles, now at z8 x245 y150                                                         
seeded 52 metatiles (1300 total tiles, 1300 non-empty tiles) in 8.9 seconds at 146.6 tiles/sec (146.6 non-empty tiles/sec)

Since I specified a tiny rectangle just one zoom level, at most 4 metatiles should have been required.

Perhaps it should either give an error message that the coordinates were out of bounds; or do some modulo arithmetic (similar to what openlayers does) to choose the appropriate tiles.