Since commit 630a67366 (refspec: add public parsing api, 2018-02-07), we now have two functions `git_refspec_free` and `git_refspec__free`. The difference is that the first one will free the structure itself, while the second one will only free the structure's contents. Use our new `dispose` naming pattern for the latter function to help avoid confusion.
Next to including several files, our "common.h" header also declares various macros which are then used throughout the project. As such, we have to make sure to always include this file first in all implementation files. Otherwise, we might encounter problems or even silent behavioural differences due to macros or defines not being defined as they should be. So in fact, our header and implementation files should make sure to always include "common.h" first. This commit does so by establishing a common include pattern. Header files inside of "src" will now always include "common.h" as its first other file, separated by a newline from all the other includes to make it stand out as special. There are two cases for the implementation files. If they do have a matching header file, they will always include this one first, leading to "common.h" being transitively included as first file. If they do not have a matching header file, they instead include "common.h" as first file themselves. This fixes the outlined problems and will become our standard practice for header and source files inside of the "src/" from now on.
This allows us to add e.g. "HEAD" as a refspec when none are given without overwriting the user's data.
As git allows you to store shorthand refspecs in the configuration, we need to do this ourselves.
It used to be separate as an attempt to make the querying easier, but it didn't work out that way, so put all the data together. Add git_refspec_string() as well to get the original string, which is now stored alongside the independent parts.
A remote can have a multitude of refspecs. Up to now our git_remote's have supported a single one for each fetch and push out of simplicity to get something working. Let the remotes and internal code know about multiple remotes and get the tests passing with them. Instead of setting a refspec, the external users can clear all and add refspecs. This should be enough for most uses, though we're still missing a querying function.