feat(frontends/lean): annotate 'notation' subterms with 'noinfo' annotation (goal: improve typeinfo generation); fix initialization problem (with annotations)

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(frontends/lean/elaborator): uninit variable

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean/server): use separate thread for processing requests in server mode, interrupt whole parser when on interruption (when collecting information)

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
chore(doc/server): update server mode documentation

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(frontends/lean/inductive_cmd): generate index for inductive decls, introduction rules, and recursor/eliminator

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(frontends/lean/info_manager): add method info_data::compare

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(bin/lmake) add --just-print (-n) option
feat(library/Makefile.common): add tags target
fix(bin/lmake): use "--always-make" option instead of touch

close #42
feat(bin/ltags): add ltags

Usage:

    ltags <ilean_files> # generate TAGS file for <ilean_files>

    ltags  # Find makefile upwards, generate TAGS file for all ilean files

close #50
chore(library/.gitignore): add TAGS
feat(emacs): add lean-find-tag (M-.)
feat(emacs): add lean-complete-tag (tab)
fix(library/unifier): use depth-first search strategy for solving class-instance constraints

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/coercion): error message

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/standard/data/quotient): import quotient from lean 0.1