Moved flush_rewrite_rules function to only trigger once on activation. This may help solve some permalink issues in the directory with some installs. Also cleaned up isolated issues where blank employee fields were filled with previous employee data.

git-svn-id: https://plugins.svn.wordpress.org/simple-intranet-directory/trunk@935264 b8457f37-d9ea-0310-8a92-e5e31aec5664