WebUI: Set global upload max limit to 10000 KB/s
Remove unneeded check on filenames

The same check is performed in fsutils::fileExtension()
Open files with ".!qB" appended to the filename

Filenames do not include ".!qB" in the file list, so the generated
path could be wrong.
WebUI: Improve translation macro.

Now we use QBT_TR(translatable string)QBT_TR.
WebUI: Drop old translation hack.
WebUI: Fix initial state of the alternative speed limits icon
WebUI: Be consistent with variable names
Merge pull request #2297 from pmzqla/filename-extension

Filename extension fixes
Merge pull request #2299 from glassez/webui_tr

WebUI: Improve translation macro.
Merge pull request #2296 from buinsky/master

WebUI: Set global upload max limit to 10000 KB/s
Merge pull request #2307 from pmzqla/webui-altspeed

WebUI: Alternative speed limits fixes
Fix 'Open Containing Folder' on unselected file.