Wrappers get an installation script

The taxonomy and book wrapperis can now be installed automatically, using the new wrapper installation script! This script eliminates the need to go through the tedious (and somewhat confusing) process of copying and renaming the wrapper files manually. The installation instructions included with the module, and the online copy of the install instructions, have been updated to explain how to use the new script.

For situations where (due to file system permissions problems) the script does not work, the instructions for installing the wrappers manually are still available. Hopefully, most users will no longer have to resort to this procedure.