version 0.4 plan

[keisukefukuda]

I'm planning a drastic update in version 0.4.

• #142 Change mpienv to an ordinary command, not a shell function, because:
  • Shell function is not available in sub shells such as $(...)
  • Shell function is not available in commands that invoke other commands, such as timeout, xargs
• performance enhancement
• Implement some feature enhancements.
  • #86
  • #59
  • #54
  • #140