Add BeanManager to a ServletContext attribute

CDI 1.0 defines a JNDI lookup as the standard way to obtain the BeanManager for resources not managed by the CDI environment. However in a servlet environment it would be much easier to get the BeanManager from a standardized servlet context attribute. This would be also a major simplification in environments that don't support JNDI (for example GAE) or that don't allow to use the standard JNDI name for the BeanManager (for example Apache Tomcat).

This topic was already discussed on weld-dev about a year ago [1]. Weld 1.0 already supports this [2] and OpenWebBeans also added this feature [3]. Unfortunately Weld 1.1 changed the attribute to a Weld-specific name in [4] which currently leads to much confusion [5].

As both of the major CDI implementations support this feature I think it should finally be put into the spec.

[1] http://lists.jboss.org/pipermail/weld-dev/2010-March/002359.html
[2] https://issues.jboss.org/browse/WELD-202
[3] https://issues.apache.org/jira/browse/OWB-360
[4] https://jira.jboss.org/browse/WELD-679
[5] http://seamframework.org/Community/GettingBeanManagerFromServletContextWithWeld11