Release 0.7.18 "Who" - Subst, Where, Apply

This release implements the Apply, Subst and | (Where) commands.

Features

• ui: Allow Shift-SPC to enter = in an expression
• Implement subst and where
• Implement the Apply command
• Implement the EQNLIB command
• Add CONSTANTS as a way to select mathematical constants menu
• Add CONLIB as an alias for ConstantsMenu.

Bug fixes

• solver: Adjust detection of "epsilon" for large values
• ttf2font: Flip x coordinates for dense fonts

Improvements

• doc: List commands that will never be implemented