Add incoming link support

[stefonarch]

Links likexrb:xrb_3rropjiqfxpmrrkooej4qtmm1pueu36f9ghinpho4esfdor8785a455d16nfshould be handled by NanoVault, opening directly the compiled send tab after unlock.
Under linux adding
MimeType=x-scheme-handler/xrb;
in .desktop file works well - just the wallet will not hande it.
test: http://nanode21.cloud/link_xrb.htm

[cronoh]

@stefonarch Support for handling the xrb: protocol has now been added in v1.0.3 - please let me know if you run into any issues!

[stefonarch]

Does not work yet , the generated desktop file is missing the relevant line:

cat .local/share/applications/appimagekit-nanovault.desktop 
[Desktop Entry]
Name=NanoVault
Comment=Wallet for interacting with Nano
Exec="/home/stef/bin/NanoVault-1.0.3-x86_64.AppImage" %U
Terminal=false
Type=Application
Icon=appimagekit-nanovault
X-AppImage-Version=1.0.3
X-AppImage-BuildId=0c471610-2da1-11a8-18ad-8bac0c756a18
Categories=Finance;
X-Desktop-File-Install-Version=0.23
X-AppImage-Comment=Generated by /tmp/.mount_NanoVa64tHpY/AppRun
TryExec=/home/stef/bin/NanoVault-1.0.3-x86_64.AppImage
`
```

But why is the wallet and adress book gone with updating? Maybe add a warning....