Workshop Demo Detector - Beta Branch

Simple detector designed to demonstrate main Pamguard developer environment, using as many Pamguard features as possible, but in a really simple way.

The detector is a very simple in-band energy detector. It will subscribe to a block of FFT (spectrogram) data and measure the background noise in a given frequency band over some time period and compare the signal to that background measure. If the SNR is >threhsold a detection starts, if it's below threshold it stops again.

This version is compatible with the Beta branch, and should be used for new plugin development.