1fichier (download): fix, detect more deleted files
1fichier (download): detect forced delay between two downloads
uploaded_net (probe): fix, work with links containing file name
cloudzer_net (probe): fix, work with links containing file name
uploading (download): fix, consider file still uploading
core.sh: enhance "online" captcha service

Detect empty credits before actually trying to solve captcha.
This commit is very useful if you use several online captcha recognition services. If you use only one, this commit has no effect.
It's quite usual that captcha service answer "no slot available". It means that when using several captcha services, busy one will be discarded.
Previously the first service was always chosen. If no online service is availalbe, "none" will be set and regular error $ERR_CAPTCHA ($?=7) will be returned (same behavior as now).

Also added real time load check for --antigate.