Irrelevant files need to be deleted from plugin.

[nit23uec]

Many file such as:
FileLoader.java
FileListFragment.java
FileListAdapter.java
FileChooserActivity.java
libs and src folder are useless for this plugin and are adding to irrelevant code.
Please correct me if I'm wrong on it.

Further, there is a problem if anyone has styles.xml already present in the res/xml folder and we use cordova plugin add command to install the plugin in the cordova project.

You are requested to correct these problems. :)