Fixed invalid package.json dependency entries.

Removed space chars that were resulting in invalid dependency
declarations, which were masked by the fact that Markdown-it's
package.json happened to install these dependencies correctly.

Author: vassudanagunta

package.json

@@ -23,10 +23,10 @@
     "test": "node ./test/test.js"
   },
   "dependencies": {
-    "entities": "~ 1.1.1",
-    "mdurl": "~ 1.0.1",
+    "entities": "~1.1.1",
+    "mdurl": "~1.0.1",
     "string.prototype.repeat": "^0.2.0",
-    "minimist": "~ 1.2.0"
+    "minimist": "~1.2.0"
   },
   "directories": {
     "lib": "./lib"