Back to snapshot.
Add in project status in readme.
Implement possibility to opt out of stdin piping.

Closes #14 and closes #13.
Implement `:default-command`, closes #15.
Bump copyright year.
Update changelog.
Document which OSes Lein can detect.
Document :default-command.
Document how to ignore stdin.
Warn about multiple stdin readers.
update 0.3.0 to 0.4.0
lein-shell 0.4.0

Signed-off-by: Jean Niklas L'orange <jeannikl@hypirion.com>