New versions of Closer libraries

Hi,

I have just released new versions of all Closer libraries, including  
Closer to MOP and ContextL.

This is an intermediate version, there are no major changes in these  
releases, apart from some minor added features and some bug fixes. I  
am currently working on supporting first-class dynamic environments in  
ContextL, and I mainly provide this current snapshot as a possible  
fallback solution in case something goes wrong. Incorporating such  
first-class dynamic environments is not a trivial operation, that's  
why I try to be extra careful here.

Nevertheless, here are some highlights of the new versions:

## Closer to MOP 0.55 ##

+ Fixed a bug in the recognition of documentation strings in make- 
method-lambda for LispWorks.

+ Added standard-instance-access and funcallable-standard-instance- 
access to LispWorks, due to popular request.

+ Added a utility function subclassp that is sometimes more robust  
than subtypep (but subtypep should be preferred whenever possible).

## ContextL 0.51 ##

+ Ensure-layered-method now accepts function designators instead of  
just function names, due to Drew Crampsie.