Make mpl ToolBar drag, pan and zoom exclusive and fix checkboxes

[JoostScheffer]

Before you could enable and disable drag, pan and zoom individually and you could select multiple at the same time. When selecting multiple the checkboxes would not update, the user can not know which tools are currently selected.

Since I do not see a purpose of using multiple tools at the same time I made them exclusive, you can only use 1 at a time. Also the checkboxes now work as intended

[JoostScheffer]

the previous implementation of color swap had some flaws:

• right clicking didn't open color picker because of float vs int problem
• after opening with right click there would be a menu to copy or paste your own value inside the box
• when clicking on a QDdraggableColor the text in the item below it would be selected
• when changing a value or swapping 2 colors, updateColors was not called

solutions to all of the above have been implemented

3 comments:

1. because I change lineEdit to Qlabel the padding changed, so I manually added padding based on font size to the stylesheet.
2. at many places I changed the strings that use % to dynamically add variables to functional strings because I think it is more readable this way
3. because I want to update the colors_text_widget i needed to differentiate between a color swap (which comes with 2 color changes) and a color change using the color picker (which comes with 1 color change). My current implementation relies on a counter and an extra signal color_changed_by_color_picker, I think this can be more elegant but I don't know how.

[rgerum]

The test*.py in .gitignore is not good as it might hinder adding new tests in the tests folder. Apart from that the changes look good. Thanks for your contribution.