max_table_width not handled for headers

[OlafvdSpek]

Noticed max_table_width in the code but didn't see it @ https://github.com/jazzband/prettytable/blob/master/README.md Is it undocumented?

Headers don't appear to handle max_table_width properly.

from prettytable import PrettyTable
t = PrettyTable()
t.max_table_width = 160
t.field_names = ['A Field Name', 'B Field Name', 'D Field Name', 'E Field Name', 'F Field Name', 'G Field Name', 'H Field Name', 'I Field Name', 'J Field Name', 'K Field Name', 'L Field Name', 'M Field Name']
t.add_row([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11])
print(t)

+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
| A Field Name | B Field Name | D Field Name | E Field Name | F Field Name | G Field Name | H Field Name | I Field Name | J Field Name | K Field Name | L Field Name | M Field Name |
+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
|      0      |      1      |      2      |      3      |      4      |      5      |      6      |      7      |      8      |      9      |      10     |      11     |
+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+

[hugovk]

It is documented in a docstring but not README:

        min_table_width - minimum desired table width, in characters
        max_table_width - maximum desired table width, in characters

It was added in https://github.com/jazzband/prettytable/commit/1001f0e94be2269ce02909f1428487882b2916e7 in 2013.

I'd welcome PRs to document them in README and to fix it for headers. It may be that min_table_width doesn't handle headers either.

[OlafvdSpek]

This is interesting as well:

t = PrettyTable()
t.max_table_width = 20
t.add_row([0, 1, 2, 3, 4, 5, 6])
print(len(t.get_string().split('\n')[0]))
print(t)

36
+----+----+----+----+----+----+----+
| Fi | Fi | Fi | Fi | Fi | Fi | Fi |
+----+----+----+----+----+----+----+
| 0  | 1  | 2  | 3  | 4  | 5  | 6  |
+----+----+----+----+----+----+----+