Fixed DateTime parsing.

Leaving _formats[0] uninitialized will cause an exception whenever
DateTime values are parsed using ParseExact(...).
new overlay groups should be a multiple of 2
move Dicom.Dump to Tools directory
remove Mixed Platforms build
restructure distribution package
update NLog to 2.1.0
show/hide overlays and apply custom color (@GMZ)
Merge pull request #56 from captainstark/master

Exception being thrown because DateTime formats array index is off by one.
update contributors in README
add missing files to Dicom.Dump project
add DICOM Compare tool to solution
Merge branch 'origin/master'
fix byte swapping for IVR single byte images
update changelog
remove Todo file from project
change URL for binary releases
Merge remote-tracking branch 'upstream/master'