Fix prefernces widget layouts.
Update change log.
Add plugin wiget int for Lua 5.2
Auto load plugins from disk when Sigil starts and remove plugins that were previously loaded if they are no longer on disk.
merge from kevinhendricks.
Merge changes from kevinhendicks.
PluginRunner: Read stderr too.
PluginRunner: Fix returning from constructor as that's invalid and leaves the dialog in a bad state. The dialog will still show in a partly initalized state and exec will still be called. Don't display cancelled message if the dialog does not show.
Add start of support for Lua plugins.
Restructure where plugin launchers are kept.
Fix layout for plugin runner dialog.
ensure / at the end of path for building properly on windows.