Add symlog colorbar scaling option

[BenWibking]

Adds a matplotlib-style symlog colorbar scaling option.

A lot of code churn is required to change bool to enum for the color bar scaling settings.

Fixes #226.

[WeiqunZhang]

• [P2] Preserve toolbar focus across dataset reopening — SmokeHarnessZoom.cpp:648
(

amrexplorer/src/qt/SmokeHarnessZoom.cpp

Line 648 in bbd0ff1

// Use a control that stays enabled across an open. The

)

At 640×480, reopening a dataset while the Level combo has focus moves focus into the image view; the next Up key pans the image. The base revision leaves focus on a toolbar combo and generates
no pan request. The added toolbar controls change focus routing when teardown disables the Level combo. Retargeting this test to the metadata tree leaves that regression uncovered. Preserve
control focus across reopening and retain the Level-focused regression case.

[WeiqunZhang]

• Request changes: the P2 focus regression remains at 62b2394.

[P2] Preserve toolbar focus across dataset reopening — SmokeHarnessZoom.cpp:648
(

amrexplorer/src/qt/SmokeHarnessZoom.cpp

Line 648 in 62b2394

// Use a control that stays enabled across an open. The

)

At 640×480, reopening a dataset with the Level combo focused moves focus into the image view; the next Up key generates a pan request. Reproduced on this head. Preserve control focus across
reopening and retain the Level-focused regression case instead of testing only the metadata tree.

The new commit changes only vector glyph code, documentation, and tests; it does not address this finding.