support flycheck commit [Drop redundant flycheck-sort-errors](https://github.com/flycheck/flycheck/commit/603ac4ef965868cc5c5bc75bdcc564605ee3cf43)
support flycheck commit [Restore mouse support in error list](https://github.com/flycheck/flycheck/commit/5441d3d2d0703511310b389b83e347d97f4f20d5)
change flycheck-error-list-make-number-cell return type (propertize string -> plist)
Fix error occurred when column is nil
Merge branch 'ncaq-support-new-flycheck'