Make the met script compatible with APCEMM 1.2

[Calebsakhtar]

I noticed that as of version 1.2 the met files produced by the scripts are no longer compatible with APCEMM.

This PR addresses that by:

• Adding a way to specify the vertical velocity "w".
• Adding a default entry (populated by ones) for the stretch.
• Adding a reference time.
• Removing the water relative humidity.

[Calebsakhtar]

@sdeastham Would you mind reviewing this?

[Calebsakhtar]

@sdeastham Just bumping this