Performance: git, stats, and check update

[PTank]

Some formatting or parts of pls are called independently of their use.

It might be nice that git is not called by default, and formatting of stats is only done according to the options specified. (I think the git part will be refact anyway to support recursion (tree option) and submodules.)

Last part, I will suggest that the check update be off by default.

[dhruvkb]

I wanted the 'check for updates' feature to be on till pls reaches a more or less stable state with relatively few bugs. As long as we're releasing new versions frequently with bug fixes, it makes sense to suggest users to upgrade. Once the releases slow down and there are very few bugs, we can turn this off.

As for Git, it is used for two purposes

1. to locate the .pls.yml file that could potentially be in the Git root
2. to get file statuses

I agree that 2 should only be performed if that field is requested. Would you be interested in filing an issue for that? Also a PR is most welcome. Same for the other parts that you have identified that can be turned off to improve performance.