Get Rid of the Dependences which requires build when npm install

[huan]

Currently, lots of developers struggle with the installation of the Wechaty because their environments leak of the build-tools.

A better way to solve this problem is to replace the npm modules that require build when install, to the module can work out-of-the-box.

Npm Module That Requires Build When Npm Install

1. node-expat(xml2json)
2. nosql-leveldb
3. ...

[huan]

Had cleaned most of them.