Added recent projects to the list

1. Added recent projects to the popup for quick access. It allows to switch to a project that you worked on before even if it isn't opened in IDE.
2. Turned on alphanumeric mnemonics for popup items for quicker keyboard access.
3. Current frame isn't disabled on the list to avoid a glitch of having the old current frame item disabled after you switched to another frame with cmd+` while FrameSwitcher popup is visible. Also, it's not obvious enough that selected item is also disabled, so it's confusing a bit when you hit Enter and nothing's happen.

PS I've put all of the changes into a single commit because they are tiny ones. Sorry if I did anything wrong, this is my first pull request on GitHub.