Version 10.11 Handle closely-spaced points

Additional releases are available elsewhere:

• For all linux distributions using the Engauge release for Flathub as part of the Flathub Project
• For all linux distributions using the Engauge Digitizer for Snapcraft from the Snapcraft Store
• For many linux distributions as part of the distribution
• For OSX from the Mac App Store on your Mac computer
• From the cygwin installer in Windows

Release changes:

• Display warning if function points are not well defined (#288)
• Handle large dynamic range in documents with four axis points (#296)
• Ensure there is always at least one curve (#294)