fixed uppercase Android dir bug

Currently the command `phonegap plugin add  https://github.com/donaldp24/CanvasCameraPlugin.git` returns the following error and the **plugin does not install**:

```
[error] Uh oh!
"[...]/plugins/com.keith.cordova.plugin.canvascamera/src/android/CanvasCamera.java" not found!
```

That is because PhoneGap looks for *src/android*, not *src/Android*. This branch simply renames the dir to fix the bug (tested and confirmed working).