Fix unmatched returns dialyzer warnings
Ensure line numbers are properly preserved in EEx, closes #2485
Merge pull request #2484 from fishcakez/dialyzer_fixes

Fix unmatched returns dialyzer warnings
Do not crash if applications are already started
Re-add deprecated local tasks
Add a note about IO.bin*
Consider multiple @external_resource entries in mix
Add a note for binary_part/3 on String.slice/3
s/file/function in IO docs
Store stacktrace before invoking callback function