Adding support for shama#72 single file download

Author: samypr100

lib/pkg.js

@@ -31,6 +31,7 @@ function NapaPkg (url, name, opts) {
       : path.resolve(this.cwd, opts['cache-path']),
     this.url
   )
+  this.strictDecompress = !!opts.strictDecompress
   this._napaResolvedKey = '_napaResolved'
   this.saveToPkgJson = opts.save
 
@@ -109,7 +110,12 @@ NapaPkg.prototype.install = function (done) {
       self._mock(['download', self.url, self.installTo])
     } else {
       self.log.info('download', '%s into %s', self.url, self.name)
-      download(self.url, self.installTo, { extract: true, strip: 1 })
+      var extractOptions = { extract: true, strip: 1 }
+      if (self.strictDecompress) {
+        // decompress module options
+        extractOptions = /(\.zip$)|(\.tar$)|(\.tar\.(gz|bz2?|xz)$)/.test(self.url) ? extractOptions : {}
+      }
+      download(self.url, self.installTo, extractOptions)
         .then(function () { cb() }, cb)
     }
   }