More changes:
- remove Client interface (reason: empty)
- introduce HTTPClient interface, which can be used for both ClientURI
and ClientJSONRPC clients (so our users don't have to create their own) (Refs #8)
- rename integration tests script to `integration_test.sh`
- do not update deps on `get_deps`
Use 0x-prefixed hex strings in client
server: Decode hex string args
Encode all string args as 0x<hex> without trying to encode as JSON
Added tests for special string arguments
Fix server handling quoted string args
Added string arg handling test cases to bash test script
