Fix ramp finding code, improve tests, compress pickle files with lzma

[BurnySc2]

• This fixes ramp finding for all maps. Some maps have large natural ramps (e.g. HonorgroundsLE) and there the wall-off placements will return None or empty set.
• Improve tests: These test now for all spawns if the ramp was found, and if it was within range of 30 to a given spawn
• Compress pickle file using built in lzma library to reduce file size by 90%