perl: Import from oldpackages, update to latest upstream, fix building, add myself as maintainer

This is the perl 5.10.0 package from oldpackages. Updated to
5.20.0(current upstream) and fixed.

A word of warning: This description will be kind of lengthy due to the
nature of perl's build system.

- Manual configuration upgrade -
When cross-compiling, perl expects you to run it's Configure script on
your host in tandem with your target via a remote shell at this point.
The old package used canned configuration files that were generated at
some time and manually edited from then on. I pretty much continue this
tradition, but reordered stuff a bit to make future updates to new perl
versions less painful.

- Host perl -
As perl needs a perl installation during build, it still builds a host
perl binary. The old package used to constantly swap that one in, which
isn't necessary with perl 5.20.0 anymore. It also doesn't need the old hack
to statically generate some headers(uudmap.h and friends). perl pretty
much handles that stuff on it's own now.
I would like to see the host-perl installation integrated into OpenWRT
tools at some point in the future, but it works for now.

- Module changes -
Some perl modules got deprecated and removed from 5.10 to 5.20, so I've
also removed the corresponding packages. I haven't added any new
ones yet.
Also, module packages used to have no dependency information between
them. I've added some, but this will be an ongoing process.

- Compatibility and testing -
Full build(that is, all options turned on) and basic functionality is
tested on mipsel, i486 and arm targets with uClibc and linaro gcc 4.8.
Other targets should also work.

- Misc -
Aside from all the perl-specific changes, I've enabled parallel build,
added myself as the maintainer, bumped the copyright notice and
fixed/rearranged minor stuff.

The perlbase-gdbm package depends on libgdbm, which isn't merged yet.
It will work with gdbm 1.10 from oldpackages, but I propose not merging
perl until gdbm 1.11 gets accepted.