System_Design: All names should be small

[georgi-g]

In our xml files name parts must be separated by spaces. During generating code the casing is ignored, but it is partially restricted in xml. see check_name in utils.py

For avoiding confusion and enforce cleaness the names used in xml should be even more restricted.

My suggestion: all names should be written in small, where name parts are separated by spaces.

Small bug in current implementation: names must not start with digits, which passes through the current regular expression.

Hint: The check removed in enum elements in da3f72a does not allow numbers e.g. "line 1", but this should be allowed.

[salkinium]

I support this. Now also officially.