backend validation is not strict enough for coordinates input

[MagdaN]

creating a kiezkassenproposal without adding a geolocation used to work but does not anymore - these are the errors:

description: ""<colander._drop object at 0x7fc538e31390>" is not a number"
location: "body"
name: "coordinates.0"

description: ""<colander._drop object at 0x7fc538e31390>" is not a number"
location: "body"
name: "coordinates.1"

Adding a marker/pin to the map is supposed to be optional.

[xi]

The errors mentioned above happen on GET. POST responds with a 200 status.

[pallix]

The frontend should not POST a value of coordinates: [null, null] but either nothing or coordinates: [0,0] to set the default value.

The backend need to be fixed and reject such requests.

[xi]

The frontend part is fixed in #1129

[pallix]

Colander issue 224 and 225 should help to fix it Pylons/colander#224 Pylons/colander#225