build: check test files

Remove __tests__ directory from ignore files in tsconfig so that IDEs
have proper type completion, and then add a negative glob for __tests__
folders to package.json files array.

Author: bschlenk

package.json

@@ -13,7 +13,8 @@
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "files": [
-    "dist"
+    "dist",
+    "!**/__tests__/**/*"
   ],
   "scripts": {
     "lint": "tslint -p .",

tsconfig.json

@@ -10,7 +10,6 @@
   },
   "exclude": [
     "node_modules",
-    "dist",
-    "**/__tests__/*"
+    "dist"
   ]
 }