Fix #153 - Log / Error Notification System

[farazs]

Fix #153. Adding log window to "Help" menu to display log messages. Highest priority log message shown in status bar (latest one only), with an icon to indicate the nature of the message.

• [x] Add menu option to "Help" menu (opens empty window currently)
• [x] Set up log window with list and headings
• [x] Create custom log handler class to populate and add to list
• [x] Add support for filter based on priority (filter visibility only)
• [x] Custom slider for selecting filter level
• [x] Add latest high priority message to status bar
• [x] Add (custom?) icons indicating message nature
• [x] Double-clicking icon or latest log message shows log
• [x] Add calls to translate for log class

[farazs]

If I want to give the Log window a shortcut of Ctrl+R, would it be okay to leave the menu option where it is and add the shortcut (it would make the dropdown menu wider to show the shortcut), or should I move it to the "File" menu or something?

[dideler]

@farazs I think it's fine if the dropdown menu is expanded because of the shortcut.

[farazs]

@dideler Alright I put in all the changes, including the shortcut. Is this okay to squash?

[dideler]

@farazs looks okay to me!

[farazs]

Squashed

[dideler]

@Freeseer/owners anyone else want to review before I merge?

[dideler]

Will merge tonight unless anyone has any objections. (Please ping me if I forget.)

[dideler]

Thanks Faraz, great work.