Fix windows event channel

Quite a few changes/fixes/updates to the Windows event channel code. Many changes were done to help address issues in https://github.com/ossec/ossec-hids/issues/224. Some testing was done by myself and @defensivedepth but more testing would certainly be appreciated. Need people who use Windows and event channel.

Tried to make the output from the `eventlog` format and the `eventchannel` format as similar as possible. Added a lot of error checking. Fixed issues where not all log messages were able to be displayed. Moved to using temporary files and atomic moves to update bookmarks.