updates to have apache2.4 compatibility

Apache 2.4 does not allow you to perform functions like 'apache2 -S' (the apache environment variables aren't loaded, giving you errors). Instead you are expected to use apache2ctl. This update switches to using apache2ctl/apachectl by default, and adds in a new variable for consumption, ctlbin. This is an analog of bin, only it gives the location of the apache2ctl/apachectl bin rather than the apache2/httpd bin.