Dimensions info

Improves some functionalities of the Dimension Widget:

• Adds QMessageBox for warning the user and informing of correct fit.
• Adds new button: Find dimensions. It is used to detect all possible dimensions, basically the ones with unique values different than the size of the data, and show them to the user. Then the user should choose, if more than needed, which dimensions are correct to reshape the data.
• When a tolerance of a dimension is modified, the size is automatically set to 0, this way when fitting it will try to find the correct size based on that tolerance.

Question: Should button Fit try to find the dimensions if the widget is clear (no dimensions) ?

If so, should it show the same as Find dimensions and try to reshape? Or should it only show the dimensions that can be fit?

For example, in the first case, if 3 dimensions are moving at the same time, all three will show, in the second only the first ones that can fit will show.

Finally, Fit does not find dimensions in any case.

Closes #10 (closed)