Update fixed-hash & uint utilities (#1078)

* [core/primitives] Update crunchy 0.1 => 0.2

* [core/primitives] Update fixed-hash 0.2 => 0.3.0-beta

* [core/primitives] Update `uint` 0.4 => 0.5.0-beta

* [core/state-machine] Fix errors emerged by fixed-hash update

* [core/state-db] Fix errors that emerged from fixed-hash update

* [core/sr-io] Fix errors that emerged from the fixed-hash update

* [core/trie] Fix errors emerged from fixed-hash updates

* [core/trie] Make use of new Hash::as_fixed_bytes_mut method in tests

* [core/sr-primitives] Fix errors emerged from updating fixed-hash

* [core/executor] Fix errors that emerged from fixed-hash update

* [core/test-runtime] Fix errors that emerged from updating fixed-hash

* [core/test-runtime] Fix an error that emerged from fixed-hash update

* [core/transaction-pool] Fix errors that emerged from updating fixed-hash

* Add From<u64> impl for hash types defined in core/primitives

* [core/client/db] Fix errors that emerged from fixed-hash update

* [core/{client/network/rpc}]: Fix errors emerged by fixed-hash update

* [node/{cli/executor/runtime}]: Fix errors emerged by updating fixed-hash

* [core/network]: Fix bug in parsing constant str

* Update Cargo.lock

- Add crunchy 0.2.1
- fixed-hash 0.2.2 => 0.3.0-beta.3
- Add static-assertions 0.2.5
- uint 0.4.1 => 0.5.0-beta.1

* [core/primitives]: Add fixed-hash/rustc-hex feature for FromStr impl

* [core/primitives] No longer provide From<u64> impl for hash types if byteorder support is not enabled

* [core/primitives] Revert to using From impl again in primitives tests

* [core/..] Fix some bugs that emerged by recent fixed-hash updates

* Update a bunch of Cargo.lock files

* [core/state-db] Re-add whitespace between attr and extern crate/mod

* [core/primitives] Fix bug in From<u64> impl for hash types using the wrong feature guard