bugfix infinite loop in Terminal.wrap

[jquast]

Closes https://github.com/jquast/blessed/issues/273 by @grayjk,

The following code enters an infinite loop:

import blessed
blessed.Terminal().wrap('\u5973', 1)

This fixes by explicit check: when

• the given individual sequence is of length '2'
• and the wrap width is '1'
• and the cur_len is '0'

we cannot break down this "Wide" character any further -- so it is allowed to flow outside the given cell.

• faulthandler_timeout = 30 is added to [pytest] in tox.ini
• Tests for East-Asian, Emoji, and ZWJ are added
• Further noting that blessed gets ZWJ wrong

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.33%. Comparing base (167c34e) to head (2526384).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #275 +/- ## ========================================== + Coverage 95.31% 95.33% +0.01% ========================================== Files 9 9 Lines 1025 1028 +3 Branches 216 217 +1 ========================================== + Hits 977 980 +3 Misses 44 44 Partials 4 4 ```

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