Make assembled bin/* files executable by default, and then attempt to
use a native tar command to build the archive, so that symlinks are
preserved, but fall back to Ant's tar task if that fails.
Add symlink to Tomcat config.
Make Ivy publish destination resolver name configurable, to support
publishing to local.
Add local repository back, to enable development without needing remote
repo.
Delete symlink if it already exists.
Fix default mapping.
Remove app/base so all custom bundles in app/main, in support of OBR
downloading into app/main (and not having to decide which dir to put
things into).