CD Detect & Execute

This release adds support for detecting blank CDRs and VCDs. It can
use alternate configuration files, and now has commandline arguments
and usage information. It can also change the polling delay.

This release includes support for multiple drives, the ability to execute multiple commands when a disc is inserted, a SIGHUP handler to reread configuration, and support for referencing the device filename or mountpoint in commands. cdde will no longer run commands on discs already in drives before cdde was started.

A problem with the sigchld handler not getting installed was fixed. More checking is performed when trying to read config file, and one is created if it doesn't exist. A nasty bug where insufficient memory was allocated for the \0 at the end of the config filename was fixed.