New upstream version 2.3

.github/workflows/maven.yml

.gitignore

CITATION.cff

README.md

pom.xml

..._algorithms/stern_library/data_structure/ThriftyList.java

src/main/java/org/xmlcml/euclid/IntSet.java

src/main/java/org/xmlcml/euclid/Line2.java

src/main/java/org/xmlcml/euclid/Real2Array.java

src/main/java/org/xmlcml/euclid/Real2RangeComparator.java

src/main/java/org/xmlcml/euclid/RealArray.java

src/main/java/org/xmlcml/euclid/RealComparator.java

src/main/java/org/xmlcml/euclid/RealRangeComparator.java

src/main/java/org/xmlcml/euclid/Transform2.java

src/main/java/org/xmlcml/euclid/Univariate.java

src/main/java/org/xmlcml/euclid/Util.java

src/main/java/org/xmlcml/euclid/Vector2.java

src/main/java/org/xmlcml/stml/STMLArray.java

src/main/java/org/xmlcml/stml/STMLElement.java

src/main/java/org/xmlcml/stml/STMLScalar.java