Merge branch 'ps/refspec-wo-the-repository' into jch

The dependency on the global 'the_repository' variable in the 'refspec.c' API has been removed by passing the hash algorithm explicitly to refspec-parsing functions and storing it in 'struct refspec'. * ps/refspec-wo-the-repository: refspec: stop depending on `the_repository` refspec: let callers pass in hash algorithm when parsing items refspec: group related structures and functions