[FIX] removed implict loading of pylab at ipython startup

    this was dangerous as it runs something like "from numpy import *"
    internally, which eg replaces __buitins__.all by np.all which
    is more fault tolerant eg if called as 'all(None)'.
    this implicit import is dangerous and introduces hard to find bugs !
[FIX] fixed output of tables with column type tuple

    tuple values where not rendered due to an issue in table.py

    Further editing of colums with types dict, set, list, tuple
    is disabled now as this caused problems when edited values
    are coverted back to the corresponding cell.