[WIP] add highway-shield gazetteer part i and update gitignore

[aparlato]

[WIP]

Shields in progress

• [ ] default
• [ ] ae United Arab Emirates
• [x] at Austria
• [ ] au Australia
• [ ] bg Bulgaria
• [x] br Brazil
• [x] ch Switzerland
• [ ] cn China
• [x] cz Czech Repulic
• [x] de Germany
• [x] dk Denmark
• [x] fi Finland
• [x] gr Greece
• [ ] hk Hong Kong
• [x] hr Croatia
• [x] hu Hungary
• [x] in India
• [ ] jo Jordan
• [ ] kr South Korea
• [x] mx Mexico
• [x] nz New Zealand
• [x] pe Peru
• [x] pl Poland
• [x] pr Puerto Rico
• [x] ro Romania
• [x] rs Serbia
• [x] se Sweden
• [x] si Slovenia
• [x] sk Slovakia
• [ ] tw Taiwan
• [x] us USA
• [x] za South Africa
• [x] e-road

Waiting for rest of data to be available to finish this gazetteer.

cc @nickidlugash

[nickidlugash]

@aparlato This looks great! I'm going to merge this in for now, and I've opened a ticket for adding coverage to the rest of the supported regions: https://github.com/mapbox/gazetteer/issues/35

[nickidlugash]

Oops, this should have been merged into mb-pages branch, not gazetteer-3. --> https://github.com/mapbox/gazetteer/pull/36