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

bugfixed inverted lon/lat parameters on RefPoint (+ added convenience ref_point->get_name())

do not display ref_points and panorama further than 25km from the current one (tunable in constant)

Use propper RefPoint::get_all() instead of requiring ref_points.local.php

moved the ref_points path to a constant.

webservice to reference ref_points is ready

first steps of add_reference.php webservice : input validation/sanitization and RefPoint class