Release 0.7.10 "Hospitality" - Interactive stack

This release primarily adds the "interactive stack" feature of HP calculators.

Features

• stack: Interactive stack and associated menu
• functions: Very basic random number generator
• demo: Add CountPrimes and RandomPlot examples

Bug fixes

• menus: Do not execute if-then-else and similar
• expressions: Avoid error testing for zero/one in power operator
• condidionals: Avoid infinite loop evaluating condition
• menu: Insert iferr-then-else correctly from menu
• constants: Skip menu entries

Improvements

• menus: Reorganize stack menu to put Dup and Drop on first page
• menu: Add error functions to Debug menu

Full Changelog: v0.7.9...v0.7.10