Arsenal - Various additions and fixes

[alganthe]

When merged this pull request will:

• Add 4 new EHs for the loadouts display:

Name	Arguments
ace_arsenal_loadoutsDisplayOpened	loadouts screen display (DISPLAY)
ace_arsenal_loadoutsDisplayClosed	none
ace_arsenal_loadoutsTabChanged	loadouts screen display (DISPLAY), tab control (CONTROL)
ace_arsenal_loadoutsListFilled	loadouts screen display (DISPLAY), tab control (CONTROL)

• Fix the accuracy stat not being accurate, the stat used the default value, now the bar and numbers shown are what they should be.
• Improve onSelChangedLeft to limit the accessory stripping issue ACE Arsenal loses weapon attachments of weapons in backpack. #6307 , using setUnitLoadout with a modified array would potentially break multiple other features or cause other issues, this is the best fix until we get the ability to add accessories to weapons in containers.
• Added some fade in for the left, right, and loadout content panels to make the UI feel snappier.
• Clear the right searchbar whenever you click on another item in the left panel (or the same one you have).

[dedmen]

https://community.bistudio.com/wiki/deleteAt

Will not issue error when -1 index is passed making it ideal for using with find(see Example 2) or findIf(see Example 3) command

[dedmen]

I can approve!