PatchEphys, IVCurve, CSVExporter updates
PatchEphys: Added check in getClampCommand for ClampParams existing (doesn't for old axopatch200data).
                    Added getClampDeviceNames to find the name of the clamp device(s) used in the protocol.
 IVCurve:      Added modes "I-Clamp Fast" and "I-Clamp Slow" to recognized ic modes.
                    Handle alternate representations of pulse start times and duration in loadFileRequested.
                    (Ultimately, these should be handled in PatchEphys.)
CSVExporter: Added option to export (x,y,y,y) as well as (x,y,x,y) format data, as done in HDF5Exporter. Verified works for
                    importing data into IgorPro.
(pbm, 6/28/2014)