Added description_ class variable to STVariable, along with getters and setters.
STVariableCollection now successfully emits a signal when a variable changes connection state, allowing STWidget to add the series to the plot.
Removed storage ring specific pv information from STWidget--STVariableCollection now handles creating and adding variables, emitting a signal when the pv is connected.
Filled in some basic code in STVariableEditor that could be used to display and edit characteristics of STVariables.