Bugfix: reset "force_update" by localizing

Provide something, so that the next "o conf commit" will not overwrite
the config file. maybe "myconfig_readonly"?

I have a patch by Jochen Wiedmann that implements a per-distribution
permanent configuration directory. The new containsmods() method in
1.52 should help to fit the patch with the rest of CPAN.pm.

Option to skip testing (Ask Bjoern Hansen).

Default Argument for make,test,look,etc. could be the last argument???

Make a preferred download method configurable (allow further download
methods via plugin?)

Allow different site preferences for index files and other files

Replace make with Make

Maintain the cache at runtime. Currently we only check it at startup.

Determine how to live without CHECKSUM files (e.g. not available)

Distribute compressed CHECKSUM files

Security layer

make plugins configurable, adjust @ISA

Distribute a file with timestamps. Interface could be: 'n 7' for new
arrivals in the last 7 days.

Start documenting the class model

Make configurable that multiple additional index files can be
integrated (for Intra-CPANs). I believe CPAN::Site did it right
anyway, so we might skip this.

Make the 'make' command itself configurable as suggested by Rujith de
Silva <rujith.desilva@ps.net>, who wants to run 'sudo make install'
instead of 'make install'. (Fixing this is delayed, because it
interacts with Make.pm)
