fixed configure test for libevent 1.x on RHEL/CentOS
removed define for u_char since it breaks some builds
tweaking u_char checks
added _BSD_SOURCE for linux to solve some lingering compile issues
note about fixed rhel, centos builds
updates to reflect problems with FreeBSD builds in 0.1.2
Allow piggybacking on libunbouns libevent
Merge pull request #40 from getdnsapi/v0.1.2

V0.1.2