Rixstoolbox

Added support for quadratic term for isoenergy line ("smile").
Modified "sum" tool to avoid summing energy or pixel axes.

Added efficiency calculations.
Added save button to shifts plot.

**Installation instructions**

**Windows**
You can use the provided installer to install RixsToolBox. Alternatively, you could download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder.

**MacOS**
Download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder using Wine.

Added tool for analytic calculations.
Fixed bug in the tools for spectrum generation and slope determination.

**Installation instructions**

**Windows**
You can use the provided installer to install RixsToolBox. Alternatively, you could download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder.

**MacOS**
Download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder using Wine.

Added automatic determination of zero energy position to energy calibration tool.

**Installation instructions**

**Windows**
You can use the provided installer to install RixsToolBox. Alternatively, you could download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder.

**MacOS**
Download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder using Wine.

Bug fixes related to changes in PyMca API and error handling. Improved speed of the tool used for aligning and summing spectra.

**Installation instructions**

**Windows**
You can use the provided installer to install RixsToolBox. Alternatively, you could download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder.

**MacOS**
Download and unpack the ZIP file into a folder and then run "RixsToolBox.exe" located inside the folder using Wine.

- Fixed problem in loading I21 files.