implements `std/osproc`

[ringabout]

requirements:

• std/cpuinfo implements std/cpuinfo #1538
• std/strtabs implements std/strtabs #1573
• std/streams implements std/streams #1536

[Araq]

Meh, I don't think we need all this, just give us a way to run external processes with stdin/out redirection.

[ringabout]

It seems that std/streams and std/streamwrappers is required to inquire input and attain output.
std/cpuinfo and std/strtabs are used in relevant functions, though they can be ignored

[ringabout]

requires #1565
requires #1561