Calculating the screen dpi on a per-monitor basis can cause
inconsistencies if multiple monitors with slightly different dpis are
used and in some cases it might not be the expected behaviour.
As such, the per-monitor dpi calculation was changed from a default
fallback to an opt in experimental feature and the default value of 96
will be used for the dpi if Xft.dpi is not set.
In the future, depending on how we decide to continue, we can either
move this setting in the global configuration section and fall back to
the X11 display dpi as the default or simply always use the per-monitor
dpi calculation. But to preserve backwards compatibility, this decision
can wait until the next major release.
The 'Github Flavored Markdown' specification says that headers must be
followed by a space character, update the changelog to respect that
requirement.
If dmenu didn't return anything we returned out of the function without
calling `waitpid` to collect the childs exit code, leaving to the child
process to be left as a zombie indefinitely. This commit makes `waitpid`
be called before the return checks are done.
