at the risk of being tarred and feathered, make PEAR2_Exception an ab…

…stract class...

README

@@ -4,4 +4,7 @@ Exception class, PEAR2_Exception also supports passing a
 cause of an exception, which can be another exception object
 or a PEAR2_MultiErrors object.  The error messages of the causes
 are used when constructing the error message displayed when
-converting PEAR2_Exception to a string.
+converting PEAR2_Exception to a string.
+
+PEAR2_Exception should always be extended by your own custom exception
+class for the package.

package.xml

@@ -9,7 +9,10 @@ Exception class, PEAR2_Exception also supports passing a
 cause of an exception, which can be another exception object
 or a PEAR2_MultiErrors object.  The error messages of the causes
 are used when constructing the error message displayed when
-converting PEAR2_Exception to a string.</description>
+converting PEAR2_Exception to a string.
+
+PEAR2_Exception should always be extended by your own custom exception
+class for the package.</description>
  <lead>
   <name>Gregory Beaver</name>
   <user>cellog</user>

src/Exception.php

@@ -101,7 +101,7 @@
  * @since      Class available since Release 0.1.0
  *
  */
-class PEAR2_Exception extends Exception
+abstract class PEAR2_Exception extends Exception
 {
     public static $htmlError = false;
     const OBSERVER_PRINT = -2;