Add merge directory support

[mwbrooks]

One feature of the Cordova project structure is the merges/ directory, which adds support for platform-specific files to replace files in www/.

The same feature should be implemented in this module to add support to PhoneGap/Build apps.

[machard]

Any updates ?

[Ventis]

This functionality should be implemented asap!

[ccollins7]

This would be very helpful.

[jason-gu]

Please fix asap, merge is a very useful feature.

[bau720123]

+1

[skd123us]

+1

[PacoBlanco]

+1