Remove gh-pages and dist from Makefile

Apparently the Makefile had been set up in order to create a GitHub
pages site with the examples on it. Since all the d3-carto-examples are
in blocks, this seems unnecessary and it was breaking `make all`. This
commit removes those targets.
Make target to install node dependencies
Basic instructions for using Make
Merge pull request #30 from lmullen/fix-makefile

Fix makefile