Add debugging output at runtime

Add debugging output at runtime

The new command line option '-D' ('--debug') increases debugging level by one.
For debugging output a user could be interested in, use the macros DEBUG() and
DEBUG2(). Functionality is equal to the ERR() macro. DEBUG2() prints stuff only
if debugging level is greater one, which means that '--debug' has been
specified more than once. This patch also includes usage of the macros for the
new template object (as debugging syntax errors in templates is one thing a
user potentially needs to do).

git-svn-id: https://conky.svn.sourceforge.net/svnroot/conky/trunk/conky1@1273 7f574dfc-610e-0410-a909-a81674777703