When using ',' as decimal separator readings are corrupted

[chwalters]

When using phone locale such that ',' (comma) is the decimal separator (such as Nederland/Dutch), the app won't allow users to enter valid data, e.g., 12.8 becomes 128 when saved, but 12,8 isn't accepted as a valid input. Reported by http://community.glucosio.org/t/cant-use-decimals-for-mmol-l-level/164/4 I was able to duplicate in Android simulator

Steps to Reproduce

Go to 'Settings->System->Languages & Input->Languages and change phone to 'Nederlands' locale. Try adding a reading into Glucosio. Readings cannot be edited correctly once the locale is changed either.