loading image in Input or result panel

[FerreolS]

When loading an image:

• if there is OUTPUT_PARAM, it should be loaded in the result panel,
• in the input panel otherwise

[buthanoid]

There is a small issue to specify: in the input form GUI, next to TARGET selection list, is a button loading OIFitsFile.
I think this one should always put the loaded oifitsfile in the input form and never in the results list.

I would say that having two buttons would be more clear rather than a button that can put the loaded file either in input either in results. A user unfamiliar with oifitsfile would maybe not notice that its file contains output params and then would not get why it does not load in input form for example.
In the other hand, having two buttons instead of one is having more buttons, so a more crowded interface.

I think this issue can also be related to the issue of the toolbar #69, since it is also a place to discuss actions and buttons.

Also see this https://github.com/buthanoid/oimaging/wiki/OImaging-actions I started writing a doc. It can also be a place to specify what actions and buttons we want in oimaging