cleaned up parity/signer

[debris]

• cleaned up parity/signer
• fixed compiling parity without ethcore-signer feature

[tomusdrw]

So the problem with this approach is that I'm pretty sure that file will be never modified along with on.rs (you will simply forget that you should change something here - cause we never compile without the feature).

That said, I like that approach - much cleaner, although will be difficult to maintain.

[gavofyork]

why do we have signer as optional still?

[tomusdrw]

It's just compilation feature - like rpc, dapps and jit although some of them are enabled by default. It has to be feature cause it's dependent on rpc

[gavofyork]

use case for rpc being optional?

[gavofyork]

it seems there isn't one - i suggest this is refactored to make rpc and signer compiled in.

[debris]

rpc and signer are no longer compile time options and are always compiled in