Properly handle eval_failure warnings, closes #2835

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Unify error reporting from EEx, closes #2833

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Conflicts:
	lib/eex/test/eex_test.exs
Improve token errors for aliases, closes #2818

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Fail to compile try without else/catch/after/rescue, closes #2797

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Update release instructions

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Conflicts:
	Makefile