Merge #tracks-notunnel-nobridge into #roads-fill

The layer #tracks-notunnel-nobridge has been merged into #roads-fill.

This unifies the various track-definitions.

Rendering changes:
The rendering order of tracks versus other roads is now determined by z_order.
Therefore, tracks are now leveled at the same level as service roads, footways, cycleways, and paths, instead of below them.
The rendering of the tracks themselves has not been altered.
Only render tracks from level 13

Oops, roads should only render from level 13 on.
Fix rendering tracks without tracktype

Make sure that tracks without tracktype render as before merging #tracks-notunnel-nobridge into #roads-fill, by providing defaults.
Merge branch 'roadsv3.0' of https://github.com/math1985/openstreetmap-carto into math1985-roads
Add a guideline on the mapper feedback loop and misspellings.
Remove rendering for highway=byway

Highway=byway should not render, as it has been deprecated for over three years.
Remove rendering for highway=unsurfaced

Highway=unsurfaced is not a highway type.
Update landcover.mss

changed commercial to construction to save gravitystorm's sanity:p
Merge pull request #193 from wonderchook/master

Update landcover.mss
Change military hatching to 16px and use global alignment

Fixes #97
Change 'beirgarten' to 'biergarten' to fix a typo
Remove rendering of natural=bay areas

Fixes #164

Any natural=bay ways I checked were on top of water anyways.
Merge pull request #199 from pnorman/bay

Remove rendering of natural=bay areas
Merge pull request #197 from mstock/fixes

Change 'beirgarten' to 'biergarten' to fix a typo
Merge pull request #186 from math1985/byway

Remove rendering for highway=byway
Merge pull request #185 from math1985/unsurfaced

Remove rendering for highway=unsurfaced
Merge branch 'military_hatching' of https://github.com/pnorman/openstreetmap-carto into pnorman-military_hatching
Remove unused military symbols.
Increase text spacing for pharmacies

Pharmacies names weren't rendereding as they were pushed too close to the icons

Fixes #176
Merge pull request #201 from pnorman/pharmacy_icon

Increase text spacing for pharmacies