Remove .lbox.
Import from gopkg.in/tomb.v1 from tests.
Drop Makefile.
Add README.
Move the main docs to the package documentation.
Simplify API and add multi-goroutine support.
Simplify new API and polish documentation.
Drop redundant information from package doc.
Drop reference to old multi-goroutine example.
Merge remote-tracking branch 'origin/master' into v2