Merge remote-tracking branch 'upstream/master'

Conflicts:
	02_Subsetting/Subsetting-Alathea.Rmd
	02_Subsetting/Subsetting-Alathea.html
	02_Subsetting/Subsetting-Alathea.md
	02_Subsetting/Subsetting-Andrew.Rmd
	02_Subsetting/Subsetting-Andrew.html
	02_Subsetting/Subsetting-Jenny.Rmd
	02_Subsetting/Subsetting-Jenny.html
	02_Subsetting/Subsetting-Jenny.md
	02_Subsetting/Subsetting_Susannah.Rmd
Environments, sorry so late
debugging

Merge remote-tracking branch 'upstream/master'

Conflicts:
	02_Subsetting/Subsetting-Alathea.Rmd
	02_Subsetting/Subsetting-Alathea.html
	02_Subsetting/Subsetting-Alathea.md
	02_Subsetting/Subsetting-Andrew.Rmd
	02_Subsetting/Subsetting-Andrew.html
	02_Subsetting/Subsetting-Jenny.Rmd
	02_Subsetting/Subsetting-Jenny.html
	02_Subsetting/Subsetting-Jenny.md
	02_Subsetting/Subsetting_Susannah.Rmd
Merge pull request #32 from meligu8/master

environments