Fix package database format to better match original pkgtools

As per report by Ruarí Ødegaard:

The formatting of /var/log/packages/* files that spkg creates differ from
the official Slackware Pkgtools. Hence when used on a system like Salix
any scripts that assume Slackware formatting may fail.

The two obvious most obvious differences are that "PACKAGE SIZE"
information is not the same format as installpkg would use. Also the
contents of install/ are intentionally left out meaning you can't use this
information to check if a package doinst.sh, without also looking at
/var/log/scripts. There are also some differences in tabbing/spacing.

With regards to the "PACKAGE SIZE" information, the official pkgtools
switch from bytes, to kilobytes, to megabytes (and perhaps one day
gigabytes if we ever get packages that big) as each size boundary is hit.
spkg uses bytes and kilobytes only and even for then formats the packages
bigger than a kilobyte differently to Slackware (by adding a space after
file size and before the K). For example, after Opera is installed with
spkg:

$ head -n 4 /var/log/packages/opera-11.60-i686-1ro
PACKAGE NAME:              opera-11.60-i686-1ro
COMPRESSED PACKAGE SIZE:   11239 K
UNCOMPRESSED PACKAGE SIZE: 36608 K
PACKAGE LOCATION:          opera-11.60-i686-1ro.txz

After Opera is installed with the installpkg:

$ head -n 4 /var/log/packages/opera-11.60-i686-1ro
PACKAGE NAME:     opera-11.60-i686-1ro
COMPRESSED PACKAGE SIZE:     11M
UNCOMPRESSED PACKAGE SIZE:     36M
PACKAGE LOCATION: opera-11.60-i686-1ro.txz
Update autotools configuration
Fix compiler warnings
Build system fixes
Fix some more compiler warnings
Updated NEWS file for 1.0.1 release