NetmfPackInstaller exceptions

[cw2]

I understand the application is in the early stages of development, but there are a few things worth including in the readme, because they cause the application to fail during startup:

• The repository location is hardcoded as C:\Keil_v5\ARM\Pack\,
• Downloading from web is not yet implemented, so the .Web subfolder needs to contain valid index.idx along with all referenced *.pdsc files.

Other than that, works a treat.