Plugin enables to define exclusive label

Exclusive label enables specify which lables ale exclusive in Jenkins
global configuration.

![](docs/images/exlcusive.png)

"Exclusive label" means that node with this label can be assigned only
if user wants this label. Example: a slave has three labels linux,
hibernate, ipv6 and ipv6 is exclusive label. The slave cannot be asigned
by label expression linux, hibernate, linux&&hibernate and so on because
this labels do not match ipv6. The slave can be assibned by expression
which match ipv6 too, for example: linux && ipv6.