showHidePlugins function added

Sets width and BG depending on wanting to show/hide
If we're showing, also perform an expand on the file manager incase it's
collapsed
(This is so we get to see both FM and plugins panes)
Trigger function on mouseover, mouseout & click

Get rid of inline JS param setting and now call new showHidePlugins
function on these events
Added an ID to this so we can target this pane
Wrap in if plus delays on findReplace

onKeyEvent actually happens on multiple events (keypress and keyup at
least)
Wrapped in an if statement now so we only trigger half the time, meaning
half the work, meaning improved usage
Clear any existing timeouts and set a new Timeout to trigger the
findReplace action in 0.5s
This means as you type it's continually clearing & setting timeouts
When you pause typing for more then 0.5s, then it'll trigger the
findReplace
The result is no lag whilst typing and giving find results within
inactivity time only