Merge pull request #728 from rmn64k/freebsd

FreeBSD support for Red
FEAT: support for read/write access on CPU's general-purpose registers added to Red/System.

Usage:
    system/cpu/<reg>
    system/cpu/<reg>: <value>

<reg>:
    - IA-32: eax, ebx, ecx, edx, esp, ebp, esi, edi
    - ARM: r0 - r15
Merge branch 'freebsd' of github.com:red/red into freebsd
Add Red runtime FreeBSD API.
Add #case Red/System compiler directive.
Restructure simple-io.
Add FreeBSD stat struct to simple-io.
Merge remote-tracking branch 'upstream/freebsd' into freebsd

Get access to cpu registers.
Add access to the edx cpu register in start.reds.
Register the rtld cleanup routine on FreeBSD.