Add to .git/info/exclude on plugin install

[andrewnicols]

It'd be great to add a line to .git/info/exclude as part of the plugin install so that it is not inadvertently added to a commit.

[FMCorz]

It's a good idea. Over the years I learned to deal with dirty repository with lots of 3rd party plugins reported with git status, so it doesn't bother me. In fact, at times I did add a plugin or two to the exclude file, only then to be confused that they aren't being reported by git.

Andrew, would you think we should:

• Add a new global config to determine whether plugin should automatically be added to the exclude file?
• Add a new flag to add the plugin to the exclude file upon plugin install/download?
• Handle the removal of the flag when deleting the files (with same flags/configs)?