Reorganise packages into sub-directories

Command used (within packages/):
for f in *; do DIR=${f%%.*}; if [ "$f" != "$DIR" ]; then echo "$f => $DIR"; mkdir -p "$DIR"; git mv "$f" "$DIR"; fi; done
Moved compiler descriptions into sub-directories

Command used:
for f in *; do DIR=$(sed 's%\(\(.\...\..[^+._-]*\)[^.]*\).*%\2/\1%' <<<"$f"); echo "$f => $DIR"; mkdir -p "$DIR"; git mv "$f" "$DIR"; done
Merge pull request #1307 from AltGr/reorg-subdirs

Putting packages in separate subdirs makes browsing much easier