Revised Abstract Element class

As suggested by cureos, Abstract Element class is actually abstract and
now generic. Makes IDICOMString deprecated.
DICOMObject updates and can now read BigEndian

Also added tests to read different filel types
Reads in most file types now

Added JPEG test
VR Injection Bug Fixed

There was a problem that elements all contained the CodeString vr type.
Also added TryGetDataValue() to DICOMObject.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	EvilDICOM.Core/EvilDICOM.Core.Tests/DICOMManipulateTests.cs
	EvilDICOM.Core/EvilDICOM.Core.Tests/DICOMReadTests.cs
	EvilDICOM.Core/EvilDICOM.Core.Tests/EvilDICOM.Core.Tests.csproj
	EvilDICOM.Core/EvilDICOM.Core.Tests/Properties/AssemblyInfo.cs
	EvilDICOM.Core/EvilDICOM.Core.Tests/Properties/Resources.Designer.cs
	EvilDICOM.Core/EvilDICOM.Core.Tests/Properties/Resources.resx
	EvilDICOM.Core/EvilDICOM.Core.sln
	EvilDICOM.Core/EvilDICOM.Core/DICOMObject.cs
	EvilDICOM.Core/EvilDICOM.Core/Dictionaries/VRDictionary.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/AbstractElement.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/AgeString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/ApplicationEntity.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/AttributeTag.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/CodeString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/Date.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/DateTime.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/DecimalString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/FloatingPointDouble.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/FloatingPointSingle.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/IntegerString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/LongString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/LongText.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/OtherByteString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/OtherFloatString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/OtherWordString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/PersonName.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/Sequence.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/ShortString.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/ShortText.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/SignedLong.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/SignedShort.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/Time.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/UniqueIdentifier.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/Unknown.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/UnlimitedText.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/UnsignedLong.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/UnsignedShort.cs
	EvilDICOM.Core/EvilDICOM.Core/Element/_ElementFactory.cs
	EvilDICOM.Core/EvilDICOM.Core/EvilDICOM.Core.csproj
	EvilDICOM.Core/EvilDICOM.Core/Extensions/IDICOMElementExtensions.cs
	EvilDICOM.Core/EvilDICOM.Core/Helpers/PersonNameHelper.cs
	EvilDICOM.Core/EvilDICOM.Core/Helpers/TransferSyntaxHelper.cs
	EvilDICOM.Core/EvilDICOM.Core/IO/Data/BigEndianReader.cs
	EvilDICOM.Core/EvilDICOM.Core/IO/Data/LittleEndianReader.cs
	EvilDICOM.Core/EvilDICOM.Core/IO/Reading/DICOMElementReader.cs
	EvilDICOM.Core/EvilDICOM.Core/Properties/AssemblyInfo.cs
	EvilDICOM.Core/EvilDICOM.Core/bin/Debug/EvilDICOM.Core.dll
	EvilDICOM.Core/EvilDICOM.Core/bin/Debug/EvilDICOM.Core.pdb
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/DesignTimeResolveAssemblyReferences.cache
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/DesignTimeResolveAssemblyReferencesInput.cache
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/EvilDICOM.Core.csproj.FileListAbsolute.txt
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/EvilDICOM.Core.dll
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/EvilDICOM.Core.pdb
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/GenerateResource.read.1.tlog
	EvilDICOM.Core/EvilDICOM.Core/obj/Debug/GenerateResource.write.1.tlog