Fix active identity when used within tracked dir

Fixes samrocketman#3

Update CHANGELOG

update changelog

git-idm v0.6

New features:

- Warn user when using a version of `git` older than 2.10.
- New option `--ssh-command` which can be specified to use a completely custom
  SSH command rather than relying on the default provided by `--key`.

Alert user about ssh-agent when using git idm use

Release 0.4

Release 0.3

Release 0.2

Do not exit non-zero when displaying the version