Adds a new rake task `plugin:checkout_compatible_all` and
`plugin:checkout_compatible[plugin-name]` that check out compatible plugin
versions.
Supports a .discourse-compatibility file in the root of plugins and themes that
list out a plugin's compatibility with certain discourse versions:
eg: .discourse-compatibility
```
2.5.0.beta6: some-git-hash
2.4.4.beta4: some-git-tag
2.2.0: git-reference
```
This ensures older Discourse installs are able to find and install older
versions of plugins without intervention, through the manifest only.
It iterates through the versions in descending order. If the current Discourse
version matches an item in the manifest, it checks out the listed plugin target.
If the Discourse version is greater than an item in the manifest, it checks out
the next highest version listed in the manifest.
If no versions match, it makes no change.
* FIX: Correct version comparison logic when comparing stable to beta
For example, version 1.3.0 should be considered higher than 1.3.0.beta3. So `Discourse.has_needed_version?('1.3.0', '1.3.0.beta3')` should return true
* Switch to use Gem::Version to compare versions
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
New `about.json` fields (all optional):
- `authors`: An arbitrary string describing the theme authors
- `theme_version`: An arbitrary string describing the theme version
- `minimum_discourse_version`: Theme will be auto-disabled for lower versions. Must be a valid version descriptor.
- `maximum_discourse_version`: Theme will be auto-disabled for lower versions. Must be a valid version descriptor.
A localized description for a theme can be provided in the language files under the `theme_metadata.description` key
The admin UI has been re-arranged to display this new information, and give more prominence to the remote theme options.
