add pdf of vignette for users without latex
Update README.md
oops..vignettes are in inst/doc upon install
wrap lines/vignettes are in inst/doc upon install
Merge branch 'master' of github.com:RGLab/SingleCellAssay
Merge branch 'master' into devel

Conflicts:
	vignettes/SingleCellAssay-intro.Rnw