sourcedialog / codesnippet textarea enhancement

[Marek Lewandowski]

Current implementation is kind of static, once the dialog is inited it will store textarea sizes, and if one will resize browser / dialog, it's not being resized with it.

Because of that reason I've decided to hide resizer in codesnippet plugin, because it does not give expected results.

Things to solve:

• Make textarea responsive, it should be shrinked/expanded along with dialog (both width and height ideally)
• Put some effort so that these two implementations will share the same solution - let's keep it DRY
• Put dialog resizer back to codesnippet plugin