Summarize the changes made to the environment

[SarthakJariwala]

Whenever the environment is updated using install or remove, conda tracks the changes made. This is accessible via conda list --revision.

The summary should also be included in ezconda.

As a separate command -

$ ezconda summary -n <env>

# prints packages installed, downgraded, upgraded, or removed in the last call
# should default to last revision made

$ ezconda summary -n <env> --all-revisions

# prints packages installed, downgraded, upgraded, or removed for the entirety of environment history

For individual commands -

$ ezconda install -n env numpy --summarize

# prints packages installed, downgraded, upgraded, or removed with the command

Maybe --summarize should be the default option

[SarthakJariwala]

Managing this with pip might be difficult. I am not sure if pip has a way of tracking what it installs, removes, upgrades.

In that case, an option might be to create a separate file for the environment managed by ezconda where pip related installs, removals, and upgrades are tracked.

This may not be an immediate issue as pip through ezconda is currently not supported but is in the plans (#3)