Fix Makefile for git repo

Removed svn export and added a simple cp command in install.

Current Makefile wont work on git repo
Merge pull request #1 from porfirioribeiro/patch-1

Fix Makefile for git repo
Revert "[cpp] Keep separate key map to ensure that references are held.  Fix toString"

This reverts commit 83d1dbbbb5b3ae415ac3ebde20bf6aee2180cf71.
readme