feat(shell/lean.cpp): use trust_lvl=10000, flycheck for EMSCRIPTEN
refactor(library/hott): remove unnecessary generalizations
fix(shell/CMakeLists.txt): merge into a single lean.js file
feat(frontends/lean): reserve notation, closes #95
refactor(library): use 'reserve' notation in the standard library
feat(frontends/lean): allow 'reserve' inside namespaces
feat(frontends/lean): validate infixl/infixr/postfix/prefix declarations against reserved notations