Show badges based on conditions

- Show "npm"-badge only for non-private packages
- Show "coveralls" and "travis" only if ".travis.yml" exists
  (This is not perfect for "coveralls", but it is currently much easier than parsing the '.travis.yml'
  for the coveralls-script)

handlebars/templates/README.md.hbs

@@ -1,8 +1,12 @@
 # {{{package.name}}} 
-[![NPM version](https://badge.fury.io/js/{{package.name}}.svg)](http://badge.fury.io/js/{{package.name}}) 
-[![Build Status](https://travis-ci.org/nknapp/{{package.name}}.svg)](https://travis-ci.org/nknapp/{{package.name}}) 
-[![Coverage Status](https://img.shields.io/coveralls/nknapp/{{package.name}}.svg)](https://coveralls.io/r/nknapp/{{package.name}})
 
+{{#unless package.private~}}
+[![NPM version](https://badge.fury.io/js/{{package.name}}.svg)](http://badge.fury.io/js/{{package.name}})
+{{/unless}}
+{{#if ( exists '.travis.yml' ) }}
+[![Build Status](https://travis-ci.org/nknapp/{{package.name}}.svg)](https://travis-ci.org/nknapp/{{package.name}})
+[![Coverage Status](https://img.shields.io/coveralls/nknapp/{{package.name}}.svg)](https://coveralls.io/r/nknapp/{{package.name}})
+{{/if}}
 
 > {{{package.description}}}