Placeholder file to default some polygons

[Ezian]

Actual behavior

Only the polygons defined through a specific XXYY-something.md file will be rendered. It can be painful to define large map with almost nothing.

Expected behavior

Allow user to passe several yaml files which contains description of tiles without MD parts.

Each yaml files can contains several parts splitted as yaml specification (--- characters) and contains a map of values indexed by a string on the "XXYY" format.

Since Yaml can be inlined, it could be easy to quickly define simple hexagons, with full support of all feature, even future one.

Example:

# Careful: 0XXX in YAML spec is an octal number. To avoid confusion, we need to put XXYY coordinates between quotes.
"0705": {"terrain": {"type": "grassland", "mixed":[{"type": "sea", "sides":["NO","SO","NE"}], "roads": ["c SE"], "icon": "fortin", "alt":"Fortin"}
"0806": {"terrain": {"type": "grassland", "mixed":[{"type": "sea", "sides":["N","NE","SE"}], "roads": ["NO NE", "NO S"], "rivers": ["N S", "N SO", "N SE"]}

Above yaml will be equivalent to:

# File 0705-something.md
---
terrain:
    type: grassland
    mixed: 
      - type: sea
        sides:
          - NO
          - SO
          - NE
roads:
  - c SE
icon: fortin
alt: Fortin
---

# File 0806-something.md
---
terrain:
    type: grassland
    mixed: 
      - type: sea
        sides:
          - N
          - NE
          - SE
      - type: plains:
        sides:
          - S
roads:
  - NO NE
  - NO S
rivers: 
  - N S
  - N SO
  - N SE
---