New command : compress all - reduces file size in folder

[kbjarkefur]

This was based on a discussion with @bbdaniels and @luizaandrade .

The command compress in Stata is rarely used. This command should take all .dta files in a folder and apply the compress command and replace the original file with the compressed file.

Options to include:

• recursive : include .dta files in subfolder to this folder

Things to think about :

• How to report when data sets cannot be opened
• Keep track of how much space was saved

[kbjarkefur]

First working version in f07b144c0f2d82129a9988fca3bd6ff0e433ec74

What is left to do is:

• Error handling. What to do if:
  • A file is not a Stata data file but has the .dta extension
  • A file is too new for the version of Stata that is the command is run in
• Outputs. Display saved desk space for each file and aggregates in a table or something