Revert inclusion of pre-bundled node-pre-gyp into Git repo.

This reverts commit 1bae44c.

Author: Moritz Raguschat

.gitignore

@@ -146,16 +146,7 @@ bower_components
 build/Release
 
 # Dependency directories
-node_modules/*
-!node_modules/.bin/
-!node_modules/.bin/node-pre-gyp
-!node_modules/node-pre-gyp/
-!node_modules/node-pre-gyp/**/*
-node_modules/node-pre-gyp/node_modules/*
-!node_modules/node-pre-gyp/node_modules/form-data
-!node_modules/node-pre-gyp/node_modules/nopt
-!node_modules/node-pre-gyp/node_modules/request
-
+node_modules/
 jspm_packages/
 
 # Typescript v1 declaration files