Add ability to parse untilTag and to stopAfterTag with namified or Group,Element syntax

[jmhmd]

Adds DicomMessage.readFile() options untilTag and stopAfterTag that terminate parsing and return the so far parsed data either up to or including the given tag. Adds normalization of namified or group,element type tags.

Use:

dicomData = dcmjs.data.DicomMessage.readFile(part10Buffer, {
    untilTag: 'StudyInstanceUID', // OR
    untilTag: '(0020,000D)', // OR
    stopAfterTag: 'PatientName', // OR
    stopAfterTag: 'x00100010', // etc...
});

Group,Element formats parsed:

(0028,7017)
[0028,7017]
0028,7017
00287017
x00287017

[pieper]

Looks great 👍

Just needs to rebased after earlier PR was merged.