Class diagram: annotations support

[klemmchr]

Resolves #963

I added support for class annotations and did some minor changes needed for this feature.
I centered the class title because it would look quite odd it the annotation and the class title would be left aligned. Also I made the class title bold to make it distinguishable from the annotations. I decided for this syntax:

class Class01
<<interface>> Class01

class Class10 {
  <<service>>
}

[coveralls]

Pull Request Test Coverage Report for Build 1052

• 13 of 28 (46.43%) changed or added relevant lines in 3 files are covered.
• 99 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.02%) to 53.544%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/diagrams/class/classRenderer.js	0	15	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/diagrams/class/classRenderer.js	2	6.98%
src/diagrams/class/parser/classDiagram.jison	97	56.95%

Totals
Change from base Build 1037:	-0.02%
Covered Lines:	2652
Relevant Lines:	4908

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💛 - Coveralls

[klemmchr]

The image in the readme needs to be regenerated. Is there a tool for this or is it done by hand?

[knsv]

@Chris579 great job! I am asking Ashish to do amore detailed review this before merging.

[knsv]

We will merge this to develop and the feature will be included in the version 9. In version 9 class diagrams will be moved from experimental to officially supported with proper docs etc.

[klemmchr]

Is there already a vague ETA for Version 9?

[klemmchr]

I'm unhappy about that. This will throw an exception if an annotation is defined before the class itself. It seems like there is no error handling about this at all, even for the members. How to treat that?

[ashishjain0512]

Merging Pull request to master.