Construct Classic (release 1.2) handles python scripting.
Construct 2 is made of Javascript. So it is doubtful that another scripting language will be added to C2 (at least, not right now I guess) since the main language to make C2 is a powerful scripting language itself.
This gives you the opportunity to make your own code into plugins, that you can then use as regular construct's objects.
Now there's no code interpretor directly into the IDE. If you really want to use Construct and feed it with code, go python and Construct Classic r1.2
Take a look at the topic Extending Construct2 with Javascript for more informations about javascript and C2. For python and Construct Classic: CC's wiki page holds the cheese.
As far as lua's concerned, it never was implemented in neither CC or C2 to my knowledge.