Added Feature - Column Align

Column - Added Align property (can be passed in constructor)
         Modified all child classes of pear.ui.Cell i.e ( gridcell,footercell,
         headercell) to add align-css. Header cell items are ordered
         based on alignment
         header cell will do more realtime resizing - this is to avoid the
         overlap issue on resize
grid.css - added left border to Headercell Option element (slide menu)
        to give more look , reduced the resizable element width to align
        header & grid cells in case of right alignment

demos are updated