fix(wms) : assign axis order param from source

[airnez]

Description

WMSSource was'nt taking the axisOrder parameter into account when provided.

Motivation and Context

Consistency: This parameter was advertised in documentation while not being used afterwards.

[Desplandis]

Thanks for the fix! It was indeed documented and missing...

I have however a few comments with our current implementation in iTowns. Reading geoserver's notes on the WMS specification, it seems that

• The WMS 1.1 always uses east/north axis ordering.

  Shall we for WMS $<1.3.0$ queries default to wsen for all CRS (instead of just EPSG:4326)?

• The WMS 1.3.0 specification mandates using the axis ordering as defined in the EPSG database.

  It would be nice again to not just handle the EPSG:4326 projection, and maybe use the projection definition from proj4 to determine the axis ordering +axis. This could be a nice addition to the CRS module.

[airnez]

@Desplandis EPSG:4326, EPSG:4269 and other CRS are hardcoded in proj4 as long/lat, not lat/long as described in epsg.org database. This means that we should redefine them by default in itowns in Crs module ? See https://github.com/proj4js/proj4js/blob/1f1494d14a0efcf078c6a9c27f82186ef82cfc53/lib/global.js#L2-L3

Moreover, what should we do if the itowns user does not define the +axis param in proj4 ? I guess that defaulting to wsen would be the option. We should then also implement other orientations like eswn or nesw.

If you are ok with this analysis I am going to push it here.

[airnez]

@Desplandis added suggested features and rebased on master since Crs module was migrated to Ts

[Desplandis]

Sounds good to me!