add --text-size-offset and --text-size-step --text-size-minimum fallbacks

[nvkelso]

When the full sized text can't be displayed due to overlap, allow Dymo to adjust the size down in --text-size-step increments until --text-size-offset value has been reached, or the --text-size-minimum has been reach (whichever is first).

[nvkelso]

Example

Asked for text that is 12 points large.
It can't fit, so...
with --text-size-offset = -4, the text could go down to 12-4=8points.
with --text-size-increment=0.5 it would get progressively smaller till it fit first by trying 11.5, then 11, then 10.5, etc.
with --text-size-minimum=10 it would try to go to 8, but since that is smaller than 10, it would stop trying at 10.

[nvkelso]

These goes into dymo-prepare-place.py as flags.
Then exported in absolute ranges in resulting text file?
So it's precalculated per feature instead going into the full dymo request.
This allows you to lock some.

With added per-feature input setting of "lock size" true/false.