semver versioning for updates

[3rd-Eden]

Currenlty the update plugin just downloads every single version change that happens upstream. This can lead to unsave version jumps. What we should do is change the version: field to work just like the version: field of NPM package.json files so users can specify a version range that they want to receive updates for.

There 2 issues that prevents us from implementing it currently and that is:

• we are using the version field to indicate the current version of file.
  • a solution for this would be reading the file from disk and re-parsing the version
  • store the value in a different key
• not all files use semver compatible versioning
  • we could transform the received version to a semver compatible version
  • ignore the update
  • accept the update
• sha1 keys from Github lookups are also stored in the version key
  • move it to a SHA key instead