The debug option specifies whether the engine will run in debug mode.
Debug mode currently only affects the caching of Spyce files and Spyce
modules. Namely, Spyce files are always recompiled and Spyce modules are not
cached (are reloaded on each request) in debug mode, which is useful for
module developers. This switch should not be used in a production
environment, because compilation will slow things down considerably! The
default value for this option is off. The values '0', 'false', and 'off'
represent production mode (as does leaving out the debug option entirely),
while any other value for this option turns debugging on.