It is redundant to pass true/false to `assert_eq!` since `assert!`
already asserts true/false.
This may, however, be controversial if someone thinks that
```
assert_eq!(foo, false);
```
is more clear than
```
assert!(!foo);
```
Use `assert!` directly instead of `assert_eq!` with true/false argument.
The `ChunksIterator` constructor is only used when either `electrum` or
`esplora` features are enabled. Conditionally build it so that we do not
get a clippy warning when building without these features.
This commit also fixes the timelock comparing logic in the policy module, since
the rules are different for absolute (OP_CLTV) and relative (OP_CSV) timelocks.
Fixes#215
