Add Support for Ti.Filesystem.File.remoteBackup

Proposed Patch to provide support for Ti.Filesystem.File.remoteBackup in Alloy's bult-in SQL adapter. 

I debated making the attribute a boolean but that created the issue of naming it noRemoteBackup or something similar. Instead I choose to stick with the existing property name, which I thought made more sense. Hence the "off" value to set the feature.  

However, smarter minds than mine can debate the name:value pair. I just want the feature support.