fix(emacs/lean-mode): Bind TAB with lean-tab-indent-or-compliete
feat(frontends/lean): add 'class' command back

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(emacs/lean-syntax.el): highlight "parameter (" properly

fix #122
fix(frontends/lean/pp): bug when pretty printing arrows

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library): remove unnecessary [fact] modifier

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(frontends/lean/pp): add necessary '@' when pp.implicit is true, otherwise produced output will not even type check

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean/server): display current option value instead of default value

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(frontends/lean/server): move option display_value to option_declarations

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean/elaborator): generate COERCION info

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean/server): add NAY and STALE status to --BEGININFO

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/data/category.lean): add very basic category theory
feat(library/data) add vectors and elimination of false to type
feat(library/data/category.lean)
feat(library/data/category.lean): more experimenting with local instances