Custom transformation improvements

[himanga]

Include:

• More SG filters, perhaps everything here: http://www.statistics4u.info/fundstat_eng/cc_savgol_coeff.html
• Option to put new columns before/after original columns
• Option to put columns at a specific position - select a column
• Table with example output
• Show count and list of selected columns, allow user to add more columns like in other platforms