Fixes and improvements for library utilities

Fixes and refactors some library utilities.
Adds .utils.DISABLE_QUERIES.
Implements synchronized terminal window size multi-process caching.
- As a side effect, fixes TUI bug where different processes get different sizes (or some fail to get at all) on terminals that require querying.
Eliminates race condition in .utils.lock_tty() multi-process integration.
- TermImageWarning is now issued instead of Userwarning when not running in a terminal or multi-process synchronization is unsupported.
Documents features that use terminal queries.

AnonymouX47 / term-image