[WIP] cmd: don't ignore _ZL_CD and allow relative paths

[phanirithvij]

• _ZL_CD is not being used for cmd script https://github.com/skywind3000/z.lua/issues/100#issuecomment-1024847432
• relative paths like z .. z ..\.. z scripts/subfolder does nothing as of now, resolved the absolute paths after calling z.lua in this PR

[skywind3000]

Thanks, I have ported the %_ZL_CD% code in your PR to the latest z.lua: https://github.com/skywind3000/z.lua/commit/3c88f8d8fa8782bf9ee47eb3a5b86e8820e247e2

However, the relative paths supporting would be implementated in the z.lua file, not z.cmd. So, that every shell can use this feature.

[phanirithvij]

Ok, got it. The help message on the readme shows relative paths so I assumed it wasn't working only in cmd.