Generic improvements issue

[gochujang-c]

Just a braindump issue, containing ideas which are not really materialized yet.

List:

• compress shared state (doing, see Compress shared checkpoint state #1)
• more evenly space checkpoints (i.e. do not transfer each one, perhaps only keep the ones at regular intervals, and skip a bit more one each node)
• improve cache size handling (i.e. the full cache directory)
• use more external libraries for commonly encountered functionality (for example, the serialization part)