read_bigwig() gains as = "Rle", returning a per-base run-length-encoded
vector spanning the queried range (an Rle for a single chromosome, or a
named RleList for several). Uncovered bases are set to the fill value
(default 0; use NA to mark them missing) (#18).
Fix remote access to large bigWig/bigBed files. The HTTP Range header was
not being set, so servers returned the entire file, crashing R or failing to
open files larger than the read buffer (#18).
fprintf statements (which R won't allow in linked libraries) and fixups for ASAN errors, mostly GNU-specific pointer arithmetic. cpp11bigwig passes both ASAN and valgrind checks (via rhub).