Tying up loose threads.

I forgot to instruct my friggin' threads to self-destruct...
Fixed some widgets not using native style in Home and Benchmark Screens
Fixed progressbar not resetting
Homescreen: Upload of benchmark results disabled by default.

We don't want to be rude :-)
Plot: Using log-scale for Copy- and Vector-benchmark.
Sparse: Added sliced_ell_matrix to benchmarks.
Added gitattributes file.
Normalize all the line endings
Removed empty temporary files.