set ver to v0.17.1

report mean read length

report error and exit when writing is failed

dont evaluate TLEN in duplication evaluation to save RAM and CPU

set version to 0.14.1

comment check_file_writable since it is always different in different OS

Update README.md

change default overlap length requirement for overlap based PE adapte…

…r trimming

Update README.md

fix crash caused by returning NULL from trimAndCut