* remove github.com/unknwon/com from models
* dont use "com.ToStr()"
* replace "com.ToStr" with "fmt.Sprint" where its easy to do
* more refactor
* fix test
* just "proxy" Copy func for now
* as per @lunny
* Update ref comment
* Generate comment on simple ref
* Make fmt + remove unneeded repo load
* Add TODO comments
* Add ref-check in issue creation; re-arrange template
* Make unit tests pass; rearrange code
* Make fmt
* Filter out xref comment if user can't see the referencing issue
* Add TODOs
* Add cross reference
* Rearrange code; add cross-repository references
* Striketrhough obsolete references
* Remove unnecesary TODO
* Add "not supported" note
* Support for edits and deletes, and issue title
* Revert changes to go.mod
* Fix fmt
* Add support for xref from API
* Add first integration test
* Add integration tests
* Correct formatting
* Fix add comment test
* Add migration
* Remove outdated comments; fix typo
* Some code refactoring and rearranging
* Rename findCrossReferences to createCrossReferences
* Delete xrefs when repository is deleted
* Corrections as suggested by @lafriks
* Prepare for merge
* Fix log for errors