Also adds documentation to Debug.php!
* Debug::isEnabled()
Checks if the DEBUG file exists on disk on the first call (stored in
memory for the duration of the instance). Returns true if debug mode
is enabled for the client.
This function also sets the internal flag for Debug::isSecure()!
* Debug::isSecure()
Returns true if debuging is enabled for specific IP addresses, false
otherwise. This is checked on the first call of Debug::isEnabled().
If you call this function before Debug::isEnabled(), the default value
is false.
Replaces 'debugMessage' by specialized debug function 'Debug::log'.
This function takes the same arguments as the previous 'debugMessage'.
A separate Debug class allows for further optimization and separation
of concern.
