This patch adds the following features:
1) Configure a color of the separator via config. It is done like
bar {
colors {
separator #000000
}
}
2) A block can have an integer entry "separator_block_width" which
sets the width of the gap which would follow after the current block.
3) A block can have a boolean entry "separator" and if it is set
to false, then the drawing of the separating line would be disabled.
This adds some code duplication which we might remove in a future
refactoring or not. Depends on whether unifying the parsers actually
makes the code better or not. I suspect it doesn’t :-).
