v1.4.0

MATLABDiffEq v1.4.0

Diff since v1.3.0

Merged pull requests:

• Add type validation and interface compatibility tests (#61) (@ChrisRackauckas-Claude)
• Improve static analysis and type stability in buildDEStats (#62) (@ChrisRackauckas-Claude)
• Bump version to 1.4.0 (#63) (@ChrisRackauckas-Claude)