* Restricting exception catcher
why:
`CatchableError` is not needed here
* Check data length before converting to `openArray[]`
why:
Getting the first entry of an `openArray[]` crashes with `IndexDefect`.
This is particularly annoying when decoding messages in rlpx.
* Added unit test using rlpx message that causes this problem to detect
This is more according to the structure of the code itself.
And also, currently some of these tests live under tests/rlp but
some under tests/common. Could use some further re-organisation
within the different tests, but this move is a first step.
including:
- fix rlp.append of BlockHeader
- add tests for rlp.readRecordType of BlockBody
- add tests for rlp.append of BlockHeader
- add tests for EthBlock roundtrip
* port kvstore from nim-beacon-chain
* remove old database backends
* use kvstore in trie database
* add sqlite dep
* avoid template param double evaluation
* clean up heterogenous lookup todo