lib: remove useless usage of `is`

Signed-off-by: Jean Privat <jean@pryen.org>
nitdoc: use `==` instead of `is`

Signed-off-by: Jean Privat <jean@pryen.org>
lib: add `Object::is_same_instance` that will replace `is`

Signed-off-by: Jean Privat <jean@pryen.org>
nitg&i: intern implementation of `is_same_instance`

Signed-off-by: Jean Privat <jean@pryen.org>
tests: replace usage of `is` with `is_same_instance`

also remove old `test_eq*.nit` tests

Signed-off-by: Jean Privat <jean@pryen.org>
lib: make `is_same_instance` intern

Signed-off-by: Jean Privat <jean@pryen.org>
src: remove handling of `is` (AEeExpr)

Signed-off-by: Jean Privat <jean@pryen.org>
grammar: remove `expr.ee`

Signed-off-by: Jean Privat <jean@pryen.org>
parser: update to remove `expr.ee`, aka `AEeExpr`, aka `is`

Signed-off-by: Jean Privat <jean@pryen.org>
c_src: update for kill is

Signed-off-by: Jean Privat <jean@pryen.org>
mkcsrc: fix copy of .h and .c files

Signed-off-by: Jean Privat <jean@pryen.org>
Merge branch 'killis' into killnitc