chore(bin/linja): add copyright
feat(bin/linja): make deps when there are missing ones
feat(bin/linja): call lean after ninja if ninja failed
doc(emacs/README.md): clean up

[skip ci]
feat(bin/linja): linja calls lean if project does not exist

close #110
chore(bin/linja): use python 2.7
feat(frontends/lean): add SHOW and SLEEP debugging support commands, fixes worker interrupted bug, and LEAN_SERVER_DIAGNOSTIC compilation mode

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(frontends/lean/server): in valid line tracking, add 'VALID' command similar to show, but marks invalid lines with a '*'

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(tests/lean/interactive): test output

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>