fix(bins): filter out empty files
fix(bins): filter out empty files

Some services do not accept empty or near-empty (whitespace) files and create errors on receiving
such files. This will filter out these files from the input before attempting to paste.

Closes #6

BREAKING CHANGE: empty files (and all-whitespace files) are now removed from the input
    Some services reject empty files and create errors on upload. They are filtered to prevent
    upload errors.

jkcclemens/bins