Do not use globally installed carton in Makefile
Setup dependency automatically in Makefile
Simplify .travis.yml
Add variable EMACS to Makefile
make should run without installing carton command
Keep Travis CI log cleaner
Use "export VAR" instead of setting it manually
Make "elpa" depend on Carton

This is to call "carton install" when Carton file is updated.
Merge branch 'var-carton'