Update PRoot changelog and roadmap.
Improve test-5996858d portability: on x86, AT_HWCAP can be "" instead of "0".
care: Print "run `/abs/path`" instead of "run `.//abs/path`" at the end of initial execution.
Revert 'care: Fix sub-reconfiguration support, ie. when executed from proot.'

Commit c68d18dc has introduced a regression, and sub-reconfiguration
is not supported anymore.

Reported-by: Jonathan Passerat-Palmbach <j.passerat-palmbach@imperial.ac.uk>
Ref.: https://github.com/cedric-vincent/PRoot/issues/72