Two improvements to eq2 filter

[BG Davis]

I've mentioned one of these elsewhere but mixed in with other topics.  Sorry!

Two changes would make eq2 even more useful.
1. Please add a "revert to default/original setting" button or box for each slider.  (Could be a simple box with an X in it.)  As it is, it's very difficult to put a slider back to its original position if a possible change turns out to be a bad move.  One must judge subjectively by eye alone.
2. Please add some sort of calibration to the eq2 (and similar) filters.  Calibration can be as simple as a series of lines (similar to those on a ruler) at regular intervals along slider paths.  Ideally, they would be numerical counters as found in earlier versions (e.g. v2.5).  Even a single marker on each slider path, indicating the default/original setting would be a great help.
The addition (or restoration) of calibration would also make it easy to return any slider to its original position.
These are especially important since eq2 in the Active Filters column only shows Contrast, Brightness and Saturation settings.  It does not show changes to RGB or initial Gamma setting.  Thus merely looking at the Active Filters column does not tell you what Gamma settings are used.

[eumagga0x2a]

1. Please add a "revert to default/original setting" button or box for each slider.

This has been implemented quite a long time ago. Just right-click the slider.

These are especially important since eq2 in the Active Filters column only shows Contrast, Brightness and Saturation settings.

A patch which adds the missing parameters has been pushed to git master.

[BG Davis]

Thank you!