Review comments to tool update in pull request #1

[bzeuner]

Hallo @XingZhao-CATR,
Thank you for the updated tool. Here my review comments:

1. The YANG heading "definitions of references" should be replaced by "grouping statements for object references"
2. The YANG heading "package object-classes" should be replaced by"grouping statements for object classes"
3. Complex data types (mapped to groupings) and simple data types (mapped to typedefs) are under the same YANG heading "package type-definitions"
4. Complex data types (mapped to groupings) should be under the YANG heading "grouping statements for complex data types"
5. Simple data types (mapped to typedefs) should be under the YANG heading "typedef statements"
6. The path expressions don't have a closing apostrophe (')
7. In case of two partOfObjectKey attributes, the path expressions of the two leafrefs are identical and reference both key attributes seperated by a comma (,)
8. In case of two reference groupings corresponding to a single class, the path expressions of the leafrefs are identical; i.e., follow the same (first) path
9. In case of two reference groupings corresponding to a single class, the uses statement of the reference grouping does not distinguish between "xxx-1" or "xxx-2"
10. A UML Interface is not mapped to a separate YANG Submodule.

[XingZhao-CATR]

@bzeuner Thanks very much for the detailed review! NO.1~6 are easy to fix.
What's the meaning of NO.10?
For now, all the rpcs are rapped in the "packages interfaces"

[XingZhao-CATR]

And about NO.7 and No.8, now the generated YANG should be right:

[bzeuner]

Hallo @XingZhao-CATR

Regarding 7.:
The issue is, that the class-4-identifier has a path that it also containing the other-id and vice versa the class-4-other-id has a path that it also containing the identifier.

According to my understanding (which may be wrong) I did expect in the class-4-identifier path only the identifier and vice versa in the class-4-other-id path only the other-Id.

Regarding 8.:
Example model from guidelines:

The path for the blue naming tree is different from the path for the red naming tree; i.e.,
blue -> class-4-ref-1: path 'model:class-1/model:class-2/model:class-4/model:uuid'
red -> class-4-ref-2: path 'model:class-1/model:class-3/model:class-4/model:uuid'

Regarding 10.:
This issue was brought up by Karthik.
Table 5.20 of the UML to YANG Mapping Guidelines
defines the mapping of an interface to a YANG submodule.
The "package interfaces" is no longer used in the Mapping Guidelines.