v0.1.1

Fixes to the placement of the labels drawn by utu.spectrum.stem, all found by looking at the figure of the passband in the ESIS instrument article.

• A label of a faint line lay along the bottom of the plot, across the axis. The lines are given to the solver as points along their length, but they stand on the baseline without covering it, so the strip of axis between two of them held no points at all — and that is where the label of a short line starts. A row of points along the baseline says otherwise.
• A label covered the leader of its neighbour, and another overhung a line. A label here is an ion and a wavelength, several times wider than it is tall, so two of them need far more room beside one another than above; and the solver measures a label by its glyphs while what is drawn is the box around them, larger by its padding.

Both are now measured, against the boxes which are drawn rather than the glyphs inside them, and the measurement is itself checked against a case which should fail.