[Uploadable.ch] New hoster

As requested in https://github.com/pyload/pyload/issues/679
Update UploadableCh.py
Update UploadableCh.py
Update UploadableCh.py
Update UploadableCh.py
[kingfiles.net] New hoster

As requested in https://github.com/pyload/pyload/issues/510
Delete KingfilesNet.py
Update UploadableCh.py
Call error instead fail in some plugins
Fix error method
Use parseTraffic instead parseFileSize in accounts
Fix and improve plugins logging
Spare code cosmetics
Replace single quotes with doubles in self.error and self.fail msg
Avoid gettext conflict due variable `_`
Extend translation support in plugins + a lot of code cosmetics and typo fixes
[XFileSharingPro] Added filevice.com to HOSTER_LIST
[XFSPHoster] Fix checkErrors
[UptoboxCom] Now multiDL should be allowed again
[PluginThread] Clean pyfile.error before task starting