replace png icons by svg from osm svn source, sort icons and remove duplicates

[Klumbumbus]

follow up from https://josm.openstreetmap.de/ticket/13084#comment:34

icon paths adapted:

• ✔ internal styles and preset
• ✔ wiki based styles and presets

outstanding external icon paths:

• ​https://github.com/species/josm-preset-wheelchair/pull/2
• ... TBD

[Klumbumbus]

Patch is ready, I will commit it today. (This should be in milestone 16.07 to not break external styles/presets for tested users for a long time.)

[Klumbumbus]

In 10706/josm:

see #13217 - replace about 166 png icons by svg from ​https://trac.openstreetmap.org/browser/subversion/applications/share/map-icons/svg reworked most of them (white background or halo, resizing, pixel alignement), draw a few new svg icons from png derived; remove duplicate icons; reorder icons; adapt internal preset and mappaint styles

[Klumbumbus]

Some stats:

In images folder there are now:

• 564 png files
• 569 svg files
• 1133 total

For the images/presets folder the numbers are:

• 162 png files
• 508 svg files
• 670 total

[bastiK]

Great work!

In the mapcss style, we now rely on the fact that big images get scaled down to 16x16 px. As this value is hardcoded and somewhat arbitrary, I wonder if this could be specified explicitly? Would it help to have a new MapCSS feature for this?

E.g. icon-size: 16; could be used to scale an image proportionally, such that the larger of the two dimensions (width / height) is 16 px.
Or icon-max-size: 16; - the same, only that an image smaller that 16 px remains unscaled.

[Klumbumbus]

In 10707/josm:

see #13217 - fix some icons; see #13204 - add reef mappaint style and icon (​https://openclipart.org/detail/172292/corals, modified, PD, CC0)

[Klumbumbus]

In 10709/josm:

see #13217, see #13204 - fix two icons