debian/create-symlinks.sh: Add script to fix start-here icons.
debian/rules: Enable fixing the symlinks.
debian/control: Add build-deps on rdfind and symlinks.

This is meant to eliminate duplication of files.
debian/rules: Enable deduplication of files.
debian/control: Build-depend on advancecomp and optipng.

This serves to further optimize the PNG files that are present in the
package, since we have a lot of files and the pacakge is way too big.

This is a micro-optimization, but it does save some space.
debian/rules: Minor refactoring of the script.
debian/control: Add build-dep on GNU parallel.
debian/rules: Optimize PNG files.