XMLNS attributes) in rendered output, with an option to keep the old
behavior.

HTMLTALParser.py, TALParser.py:
    Mark TAL, METAL and TAL/METAL-related XMLNS attributes in the
    attribute list; the old macroHack marking is subsumed in this.
    The marking is a third value in the list item describing the
    attribute, saying "tal", "metal" or "xmlns".  All TAL and METAL
    attributes are marked; only XMLNS attributes whose namespace URI
    value is the special marker for TAL or METAL are marked.

TALInterpreter.py:
    - Get rid of the non-functional 'html' keyword argument.
    - Add new 'showtal' keyword argument to constructor; this defaults
      to -1, which means that the value should default to 0 if TAL
      expansion is requested (through the 'tal' keyword argument) and
      1 if TAL expansion is not requested.
    - In do_startEndTag(), don't special-case empty HTML tags; this is
      already taken care of by TALGenerator.
    - Implement the showtal behavior: when this flag is false, don't
      output TAL, METAL and XMLNS attributes (that are marked as such
      by the parser).
    - Fix a bug: <img src="foo" tal:attributes="src nothing"> should
      render as <img>, not as <img src>.

TALDefs.py:
    Bumped TAL_VERSION to "1.0.1"

driver.py:
    New command line option -t to show tal in output

README.txt:
    Update TO DO list.