Master Table at March/2018, Observations time range selection

This version of Swift-DeepSky add some features and improvements to the selection of observations and "detect" image output:

• Include options --start and --end allowing a time-slice for observations selection,
• --start/--end may be used separately to consider open (time) intervals on one side or the other;
• Option --upload is now enabled by default;
• Output GIF image from detect include the detected objects labels now, improving user visualization

The default Swift observations Master table has been updated to contain observations until 28/Feb/2018.