Draft tutorial documentation
Sectioning of two tutorials
Started adding information for tutorial on dimensionality reduction
Finished creation of dimensionality reduction tutorial
Merge branch 'master' into belfast-tutorials
Added some text to tutorials
Added tutorial on Steinhardt parameters
Merge branch 'belfast-tutorials' of https://github.com/plumed/plumed2 into belfast-tutorials
Added details on trajectory to belfast-10 tutorial
Added links to videos
Fixed a couple of typos
Merge remote-tracking branch 'origin/master' into belfast-tutorials
Merge branch 'belfast-tutorials'