LaTeX paper minor revisions.

Add support acknowledgement
Remove parens around one reference due to text flow
Add line numbers globally to assist reviewers
Correct Makefile to build all prior to latex specific script
Merge branch 'master' of https://github.com/scikit-image/scikit-image-paper into latex_paper
Manually resolve merge conflicts in Makefile and skimage.tex

Conflicts:
	Makefile
	latex/skimage.tex
Merge pull request #64 from JDWarner/latex_paper

LaTeX paper minor revisions