doc(README.md): add details on how to use tincr chrome extension for auto-reload

Note that it doesn't work on Linux.

[skip ci]
fix(js/platform.js.map): add missing platform.js.map file
feat(tutorial1.org): begin introduction to dependent type theory in Lean
fix(tutorial1.org): fix typo
feat(tutorial1): finish first rough draft
fix(tutorial1.org): typos and suggestions
feat(01_The_Language_of_Dependent_Type_Theory.org): rename file
feat(02_Propositions_and_Proofs.org): add rough draft of second chapter