First Intention Action (replacing get(...) with [...])

This pull request attempts to implement an intention action for users coding in Kotlin:
When they use an expression of the form Foo.get(x, y...), the intention action will enable a shortcut for them to change it to Foo[x, y...].
The main addition is in the file ReplaceGetWithSquareBracketsIntention.kt.

There are probably quite some things on improve on for this pull request.
One of which is how the intention action will only display if the caret is placed before the get(...) and not elsewhere.
I apologize for any unsatisfactory code as I am new to Kotlin as well as the IntelliJ ide.
I hope to learn more about Kotlin and code better and more efficiently.

-Lingzhang