Simplify bounds checking
Simplify bounds checking

Rather than long-winded borrowing, we can simply consume our input
lon, lat and bounds when we check them, since we're assigning the
result to new variables anyway.

urschrei/rust_bng,urschrei/lonlat_bng,urschrei/lonlat_bng,urschrei/lonlat_bng,urschrei/rust_bng