4.0

1. New TGeo classes support:
   • browsing through volumes hierarchy
   • changing visibility flags
   • drawing of selected volumes
2. New 'flex' layout:
   • create frames like in Multi Document Interface
   • one could move/resize/minimize/maximize such frames
3. Significant (factor 4) I/O performance improvement:
   • use ArrayBuffer class in HTTP requests instead of String
   • use native arrays (like Int32Array) for array data members
   • highly optimize streamer infos handling
4. TH2 drawing optimization:
   • if there are too many non-empty bins, combine them together
   • when zoom-in, all original bins will be displayed separately
   • let draw big TH2 histogram faster than in 1 sec
   • optimization can be disabled by providing '&optimize=0' in URL
5. TF1 drawing optimization:
   • function 'compiled' only once
6. Reorganize scripts structure:
   • move all math functions to JSRootMath.js
   • TH2, TF1, THStack and TMultiGraph painters moved into JSRootPainter.more.js script
   • reduce size of scripts required for default functionality
7. Update all basic libraries:
   • d3.js - v3.5.9,
   • jquery.js - v2.1.4,
   • jquery-ui.js - v1.11.4,
   • three.js - r73
8. Implement ROOT6-like color palettes:
   • all palettes in range 51...112 are implemented
   • by default palette 57 is used
   • one could change default palette with '&palette=111' in URL
   • or palette can be specified in draw option like '&opt=colz,pal77'