thead filckering on Chrome

[rrd108]

For version 0.1.24 when you have multiple tables with sticky headers and use fixedOffset the headers are flickering on scroll.

Solutin is found at #112

Change

base.$originalHeader.css({
    'position': 'fixed',
    'margin-top': base.options.marginTop,
    'left': newLeft,
    'z-index': 3 // #18: opacity bug
});

to this

base.$originalHeader.css({
    'position': 'fixed',
    'margin-top': base.options.marginTop,
    'top': base.options.fixedOffset,
    'left': newLeft,
    'z-index': 3 // #18: opacity bug
});