Fix BPExamplesMorph Resizing

[JoeAtHPI]

Resolves child morphs of BPExample not using the full width of their parent, causing unwanted line breaks for wide browsers

becomes

when deleting intentional back spaces

[ekrebs5]

One small problem: In some cases a lot of code seems to lead to the inner Morphs being layoutet too big, even tough with line breaks the code does not need that much space? Maybe we should add a max size if possible.

Picture attached, this also e.g. happens in BPTreeSceneMorph>>#resetForm

[JoeAtHPI]

@ekrebs5 the problem was the set width of the text field in editFieldFor: model text: getTextSelector onChange: setTextSelector onAccept: acceptTextSelector, which would always be the length of the text (also behaving like that in the old version). for the example morphs i set the property manually to #spacefill, along with the argument/'self'/'script' container. no overflow now + no need for max width

[ekrebs5]

Finally had time to try this again. Looks good and can be merged :)