Beta build 55

- Added support for Nikon D3100 and D7000

- Fixed white balance problem with many Sony models

- Improved performance on single core machines

- Reduced memory usage

- Changes to sharpening implementation

- Deleting a file for which a DNG version exists in the same directory won't cause its settings file to be deleted

- Bug fix: lens name in metadata tab wasn't erased when switching to a raw file for which lens name extraction isn't supported yet or the data isn't available

- Bug fix: Program crashed on metadata tab with some Canon camera body - lens combinations

- Beta expiration extended until June