When pulling/pushing/fast-forwarding a branch, show this state in the branches
list for that branch for as long as the operation takes, to make it easier to
see when it's done (without having to stare at the status bar in the lower
left).
This will hopefully help with making these operations feel more predictable, now
that we no longer show a loader panel for them.
The model will be used for logic, so the full hash is needed there; a shortened
hash of 8 characters might be too short to be unique in very large repos. If
some view wants to display a shortened hash, it should truncate it at
presentation time.
We've been sometimes using lo and sometimes using my slices package, and we need to pick one
for consistency. Lo is more extensive and better maintained so we're going with that.
My slices package was a superset of go's own slices package so in some places I've just used
the official one (the methods were just wrappers anyway).
I've also moved the remaining methods into the utils package.
Branches can now be colored based on their prefix, if it matches
a user defined prefix in the config file. If no user defined
prefix matches, then it will fallback to the defaults: green for
'feature', yellow for 'bugfix', and red for 'hotfix'. All
remaining branches will be set to the default text color.
