Remove non-uniform spacing

[Done]
 - Remove non-uniform spacing

[To Do]
 - Implement data binning
 - Grid line for scatterplot and Gatherplot (One line becomes rectangle)
 - Integrate visdock
 - Interface simplification
 - Add axis subdivision
 - Direct manipulation
 - Icon refinement (aggregate)
 - When the nomaRound and noma
 - Continuous color dimension