Release 1.0.0

[malept]

This issue should describe the criteria for releasing 1.0.0.

• Add contributing/support/CoC docs #120
• Drop callback support (Drop callback support #138)
• Drop Node 4 support (Drop Node 4 support #145)

[malept]

• I'd like to finish Add contributing/support/CoC docs #120 before we release.
• What do you think about dropping callback support? We can mention in the docs to use nodeify if callbacks are required.

Drop Node 4

I don't want to drop Node 4 support until LTS support is dropped by Node itself at the end of April. That can be 2.0.0 (or whatever major version we end up on at that time).

[fcastilloec]

I like the idea of dropping callback support only. That will keep with semver definitions. Great idea.
Regarding #120. I like the idea of basing them on electron-packager, feel free to do it.