Allow running in strict mode

[S-S-X]

Allow setting strict mode in configuration file.

When strict mode is enabled it should throw errors to fail tests immediately if:

• Deprecated engine functions are used.
  • Example: ItemStack:get_metadata() (method is deprecated)
  • Most functions already do this because there's no implementation for most deprecated functions.
• Engine API function call would return error.
  • Example: InvRef:set_size("main", -1) (function returns false to indicate error)
• Values or types that can be converted are supplied
  • Example: InvRef:set_size("main", "1") (string instead of number)
  • Example: InvRef:set_size("main", 1.2) (floating point truncated)

Possibly could also allow types for strict mode, something like:
strict = types,deprecated to throw error for type conversions and deprecated calls.
strict = all to throw error on anything not considered accurate or completely valid.

Also link to #5

[S-S-X]

From closed duplicate #61

Option: lazy failure to allow continuing test case and make calls to deprecated functions fail test case after completion.
This allows prioritizing other assertions and completion of whole test cases even with deprecated function calls but would still fail at the end.