Package metadata, the first phase

[dahlia]

This pull request partially implements the metadata format for Nirum packages. It has to be named as package.toml in the project root, and currently consists of the following fields:

• version: A required semver string of the package e.g. "1.2.3".
• authors: An optional array of author tables.
  • name: A required string of the author.
  • email: An optional email address string.
  • uri: An optional URI to the author website.

The version goes to Python setup.py metadata's version field, andauthorsgoes toauthor/author_email` fields. For example, where the following metadata is given:

version = "1.2.3"

[[authors]]
name = "Eunchong Yu"
email = "kroisse@gmail.com"

[[authors]]
name = "Hong Minhee"
email = "hong.minhee@gmail.com"

[[authors]]
name = "Kang Hyojun"
email = "iam.kanghyojun@gmail.com"

The following setup.py code is built:

setup(
    ...,
    version="1.2.3"
    author="Eunchong Yu, Hong Minhee, Kang Hyojun",
    author_email="kroisse@gmail.com, hong.minhee@gmail.com, iam.kanghyojun@gmail.com",
    ...
)