Add to `units::parse` the complete suit of hex unit parsing functions:
- remove prefix
- assert without prefix
- parse with or without prefix
- parse with prefix
- parse without prefix
- parse prefix unchecked
Refactor `bitcoin` to use the exact function we need, removing code
duplication.
This is a breaking change to `units`, it does however keep the current
re-exports from the public, now empty, `bitcoin::error` module.
Move the `strip_hex_prefix` helper function to below where it is called.
Note that I was the original author of this helper so there is no excuse
for it being above - bad Tobin no biscuit.
When creating the ParseIntError in `hex_u32` I (Tobin) just cargo cult
programmed the generic stuff without thinking.
- The `is_signed` field is used to denote whether we were attempting to
parse a signed or unsigned integer, it should be `false`.
- The `bits` field should be directly set to 32.
Move the following unit types to the new `units` crate:
- `locktime::absolute::{Height, Time}`
- `locktime::relative::{Height, Time}`
- `FeeRate`
- `Weight`
Also move the `parse` module as well as constants as required.
Do minimal changes to get things building:
- Feature gate on "alloc" as needed.
- Remove rustdocs that use `bitcoin` types.
- Re-export units types so this is a non-breaking change.
- Fix import paths.