x,y relative positions can be negative, although its rare

changed code so that we can concatenate one or more ref_points files to ref_points.local.php

Refacto of Tiles handling and simplified a bit file naming for tiles/params.
By the way, fixes #297

THIS COMMIT BREAKS FILE LAYOUT AND REQUIRES MIGRATION (SEE BELLOW).

To migrate data :

cd tiles
find . '*.jpg' -exec rename 's/[^\/]*_(([0-9]{3}_){2}([0-9]{3}))/$1/' {} \;...

moved the ref_points path to a constant.

now displays the circles with the same color as on the pano (sortof...)

typo

fix array format that seems not to work with some PHP versions

Added sanity checks

adds a rm_reference.php webservice and fixed the typing from/to ini files

webservice to reference ref_points is ready