Read the key, element pairs from a java properties file
Follows the java properties file format and tested against the Java 6 version of java.util.Properties
Args:
propfile: a valid file object (as returned by open(filename))
Returns:
The property key and elements as a dict
Raises:
IOError: if file operation fails with I/O related reason
Corresponds to java IOException in Properties.load()
UnicodeDecodeError: if the property file has malformed \uxxxx encoding,
Corresponds to java IllegalArgumentException in Properties.load()
AttributeError: if invalid object was provided for file object
Corresponds to java NullPointerException