TODO: load test cases as python modules, or separate scripts using the source command?

Include them after the other scripts with -ex in GDB command line

- Commented out messages for memory allocations outside a parser context
- Commented out fallback for when a parser vtable can't be found in the dictionary, as that should be an error
- Added debug line printing the address that was not found in the vtable name->address dictionary

- In h_many, env->sep is going to be NULL, avoid trying to add it as a parser object

Hopefully there will be fewer incomprehensible errors now

Removing gdb.parse_and_eval and just making gdb.Values directly

name_from_vtable() needed the top_level_parse attribute

Extracting parser environment information will be done through the GDB Value API

- handle parser names being None in HammerParserBacktrace
- figured out subscripting, so the stringly typed code in the Env
classes can be replaced

Also removed an unused dict

HParserEnv.name_from_vtable() should be automatically called now

Makes the window resizing itself a bit more tolerable

super().__init__() needed to be explicitly called for superclass instance variable to be initialized

- fix wrong signature for SeekEnv.__str__()