ZHANG, Ruda October 04, 2018:  Corrections to manifold learning [3da1eb0]
ZHANG, Ruda September 30, 2018:  Test math formats compatible with Pandoc. [423e53c]
ZHANG, Ruda September 30, 2018:  CSS redesign; more edits. [dd44d96]
ZHANG, Ruda March 23, 2018:  Global remove trailing whitespaces [2b7ff90]
Ruda Zhang July 05, 2016:  Add leaflet, QGIS; notes on decision trees. [9f2e957]
Ruda Zhang June 26, 2016:  add category tag to wiki pages [a9b356c]
Ruda Zhang June 26, 2016:  use canonical filename and no internal H1 [eeca8ff]