builder: update terminal title when build progress
builder: update terminal title when build progress

This tries to be similar to jhbuild in that we update the
terminal title at various stages of the build process.

This is useful for casual command line users. It is also useful
for applications automating the use of flatpak-builder as then
can display progress to the user without having to parse all
stdout content.

For build systems that support progress (such as ninja), this
allows for both a build message (the term title) and progress
bars (generated from %d/%d build system output).

flatpak/flatpak,handsome-feng/flatpak,handsome-feng/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak,handsome-feng/flatpak,handsome-feng/flatpak,flatpak/flatpak,flatpak/flatpak,handsome-feng/flatpak