fix string use-after-free (#75)

[TheRedDeveloper]

Addressing #75

• Use owned_strings to keep strings alive
• Copy unknown-lifetime strings
• Introduce text_literal and text_string methods for differentiation

[TheRedDeveloper]

Rust frees dynamic id label strings, this leads to use-after-free in the debug tools, which leads to crashing. Dynamic label strings should not be supported.

[TheRedDeveloper]

Renaming closed the PR. Opening a new one.