move repo into standard user repo path: /fdroid/repo

refs #2685
Adding styling to the Kerplapp bootstrap index page.

Further refinement for #2668 A first pass at adding some styling to the Kerplapp
bootstrap index page to make it a little bit easier on the eyes. Thanks to @doeg
for expert design advice.
better debug messages from doSymLink()
delete fdroid.client.apk symlink before copy to make sure its updated

If fdroid.client.apk is present, then the symlink fails, and it does not
get updated.
add current IP/URL to the repo metadata

This sets the metadata in the index.xml, including the URL and categories.
include the repo fingerprint in the repo URLs #2613

This takes the code from FDroid for calculating the fingerprint of the repo
signing key. Once this code is included in FDroid, it should use FDroid's
own DB.calcFingerprint() to replace KerplappKeyStore.getFingerprint().

This relies on this merge request being included in fdroidclient:
https://gitorious.org/f-droid/fdroidclient/merge_requests/45
show the fingerprint on the bootstrap screen  #2454
set repo URL to UPPERCASE for a more compact QR Code

This relies on things being included in fdroidclient.git, see #2685
refresh IP and repo URL when changing HTTPS pref or repo setup

#2580