Use riemann.common/event to add :time in folds/count

This ensures that the synthetic event generated (when
no events have come in yet) will have a :time attributed.

[Fixes #365]
Merge pull request #370 from DanielleSucher/fix_365_folds_count_event

Use riemann.common/event to add :time in folds/count
Add source file and line to deprecation notices
Merge pull request #371 from DanielleSucher/add_file_and_line_to_deprecation_notices

Add source file and line to deprecation notices