Modify event query time function

The `time()` function always returns UTC, whereas `current_time()` is slightly better, linked to the timezone settings, and doesn't seem to cause the error. See: http://codex.wordpress.org/Function_Reference/current_time
Merge pull request #6 from joshuadavidnelson/patch-2

Use current_time() so proper timezone is reflected, props @joshuadavidnelson