Fix to issue 34: Allow user to copy datalogger type, gain and sensor type to other stations

The StationWidget now has two more buttons "Copy Type & Gain To More Stations" under Datalogger and "Copy Type To More Stations" under Sensor. Clicking either one will bring up a child dialog window. "Copy Type & Gain To More Stations" has two checkboxes for type and gain, with a label indicating the value that will be copied to one/both fields. "Copy Type To More Stations" has a label indicating the value that will be copied to selected stations' sensor types. The dialog has a table widget of all stations in inventory, and similar to the inventory tree, the user can single click on stations, hold ctrl to select multiple individual stations, or hold shift to select a range of stations.