This adds a new file defines.h and moves all the Csocket specific stuff from
main.h into this new file.
Then this makes Csocket use ZNC's DEBUG() macro for its debug output which
means this can now also be enabled by running znc --debug.
git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1445 726aef4b-f618-498e-8847-2d620e286838