Replace exists? with exist? to avoid warnings.
Make read_last_event public, remove arguments, use require_relative.
Removed some intermediate variables.
Added changes so far for 0.6.1.
Be more memory efficient by clearing and reusing existing pointers where possible.
Updated change note.
Added a couple tests for read_last_event.
Added known issue for JRuby x64.
Merge branch 'ffi2' of https://github.com/djberg96/win32-eventlog into ffi2

Conflicts:
	lib/win32/eventlog.rb