[UI] Importing data should be more convenient

[jsnel]

From: #1

joernweissenborn commented on Feb 10, 2016
The current way to import datasets is far to cumbersome and feels like win 3.11

Context:

Users often want to have quick look on the data they just acquired. It steals like 10secs of your life importing a file in glotaran which is too much.

Proposal:

Glotaran should remember the last folder when using the the open dataset option
Option screen: Glotaran should offer the option to import arbitrary file endings and let the user choose which scheme to use
Personal file format: the user should have the option to import e.g. a .dat as "time explicit" file and make Glotaran remember the choice for future so it will not ask for every one of the 100 datasets
drag'n'drop: dragging a file (or multiple) from explorer, nautilus, etc into a "Dataset" folder in the tree should add the datasets. If the dataset is not recognized the option screen for data import should opened.

joernweissenborn commented on Feb 10, 2016
Since GlotaranApp will stay a Netbeans App, I think this changes can already be done for Glotaran 1.X and be inhereted by Glotaran2 without problems..