Snbt fixes

[booleanbyte]

Fixes issue with the SNBT reader when reading empty compound, list and string tags. Fixes issue #24.
Also fixes number formatting of float and double tags when writing SNBT to be in decimal format, instead of scientific format.

[Camotoy]

Please fix the diffs on the FloatTag and DoubleTag classes.

[booleanbyte]

Ah, those are line ending changes, changing from windows style to unix style.
After investigating a little, I'll have to admit it seems I goofed up line endings back when I initially created the SNBT implementation, and committed all the source files I touched back then with windows line endings.
Originally they have all been unix style line endings, currently there is a mix of line endings on the index, and the windows style I accidentally introduced are in minority, so I would argue this is a step back towards normality. Are you sure you want me to change these to use windows line endings again for the sake of the diff?
In regards to reviewing the changes, github lets you filter away whitespace changes in the diff view.

[booleanbyte]

You can run git ls-files --eol to see how the line endings differ on the index.

[Camotoy]

Hmm, yes, we would prefer Unix whitespace.

[booleanbyte]

I notice I should go over the custom additional float and double array tags as well, to get them in line regarding number formatting as well.

[booleanbyte]

Hi, since this has been inactive for a while now, I've recently taken a look over this again if there where anything missing, and in doing that I've figured there where a few more things that should be fixed here.
Considering that, along with the line endings issue that I get a feeling is blocking here, I've decided to close this PR for now, and I'll rather submit a separate fix for the all line ending inconsistencies first, and then come back with another PR for the rest later when I'm more sure I've got the rest of the SNBT capabilities fixed and better tested.