Changes in version 1.0.0rc5 (since 1.0.0rc2)
  - build-system
    * lot of cleanup, refactoring and bugfixes
    * '.*' is now a valid version argument
    * 'system' isn't a synonym for OS/kernel any more. It defines a target operating system like RHEL6, macOS1014. 
    * checks for supported system, OS and compiler
    * compute default for the number of parallel make jobs
    * calling pbuild::make_all in a build-script is now deprecate

  - modulecmd
    * --with option of sub-command search now accepts a comma separated list of strings
    * better load hints
    * log modules loaded to syslog
    * PMODULES_ENV is exported only on content changes
    * bugfixes and cleanup

1.0.0rc4
  - never tagged
1.0.0rc3
  - never tagged