[iManGaaX]

Summary

CElement::OutputToXML only wrote custom data and child nodes, so every element saved by saveMapData came out empty (<object>) and the file could not be loaded back

Adds CElement::WriteSpecialData, the counterpart of ReadSpecialData, and implements it for every element type the map loader supports: object, building, vehicle, ped, pickup, marker, blip, radar area, team, water and dummy. also writes the shared id / attachTo attributes and adds XMLColorFromInt for colour attributes

Colshapes are left out on purpose - they have no XML loading path, both map loaders fall through to a dummy element for them

Also teaches loadMapData about <building> nodes, which CResourceMapItem already supported

This PR also fixes #1473

Test plan

Created one of each element type, saved them with saveMapData, then loaded the resulting file back with loadMapData

Before ->
<object note="custom data" />

After ->
<object model="1337" posX="1.000000" posY="2.000000" posZ="3.000000" rotX="0.000000" ... alpha="255" scale="1.000000" note="custom data" />

Checklist

• Your code should follow the coding guidelines.
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