Merge pull request #33 from tkenakka/master

[mbpi] Airtel India MMS APN settings added
[mbpi] Updated Telenor DK MMS settings

Removed obsolete entry, moved the working one to the top of the list.
Check the validity of serviceproviders.xml at build time
[mbpi] Added the name for Telenor DK internet AP
Merge pull request #34 from monich/telenor.dk

Updated Telenor DK MMS settings
Merge pull request #35 from monich/xmllint

Check the validity of serviceproviders.xml at build time