VFS: Support for copying between custom mountpoints
VFS: Support for copying between custom mountpoints

salman-kamkoriwala/OsJsSample,Rxswyers/OS.js,omet-ca/omet-desktop,omet-ca/omet-desktop,Rxswyers/OS.js,Rxswyers/OS.js,andersevenrud/OS.js-v2,omet-ca/omet-desktop,Rxswyers/OS.js,salman-kamkoriwala/OsJsSample,omet-ca/omet-desktop,omet-ca/omet-desktop,andersevenrud/OS.js-v2,andersevenrud/OS.js-v2,andersevenrud/OS.js-v2,salman-kamkoriwala/OsJsSample,salman-kamkoriwala/OsJsSample,salman-kamkoriwala/OsJsSample,Rxswyers/OS.js,andersevenrud/OS.js-v2