This patch extends `app.toml` and adds the following section with these
default values:
```
[planetmint]
watchmen-endpoint = "localhost"
watchmen-port = 7401
```
A global singleton `plmntConfig` is introduced to save and access the
values similar to how cosmos does it (see
vendor/github.com/cosmos/cosmos-sdk/types/config.go).
Different environments can be managed by changing the values in
`app.toml` and restarting the daemon.
// Closes#53
Signed-off-by: Julian Strobl <jmastr@mailbox.org>