command.c breakup

Hi All,

With regards to the proposed command.c refactoring...

I've done it by removing command.c and replacing it with

portal.c
alter.c
lock.c
namespace.c

Is that a good idea? Will it break too many outstanding patches?

Basically the portal fetch/destroy commands go in portal.c, all the Alter*
commands with their static helper functions go in alter.c, the single
LockTable command goes in lock.c and the CreateSchema function goes in
namespace.c. I anticipate that a few more functions will eventually be
created to go in namespace.c

I have also broken up the command.h header file into four separate
correspondingly named header files, and removed command.h itself.

The next step after this would be to move a lot of the redundant code in
alter.c into static functions.

Thoughts?

Chris