PEAR_PackageUpdate::isIncludable -- 
   Determines whether or not a file is includable.
  
Description
   Determines whether or not a file is includable. This method is used to
   ensure that the driver class file can be found and included.
  
Parameter
   
- string $path
 
       The path to the file to check. The path should be a subdirectory of
       one of the directories in the include path.
      
 
  Note
   since 0.4.2
  
This function can be called
statically.
Return value
   boolean - TRUE if the file is includable, FALSE otherwise.