Brief summary of issue / Description of requested feature:

selectSection returns true rather than if given a window name for a window that doesn't exist, and doesn't treat "main" as a valid window option, returning true but never actually changing the selection.

Steps to reproduce the issue / Reasons for adding feature:

1. selectString("main", 10, 5) -- returns true, doesn't select anything
2. selectString("not a window", 0, 10) -- returns true, doesn't select anything

Error output / Expected result of feature

Make selectString("main", 10, 5) == selectString(10, 5)
Make selectString("not a window", 0, 10) return false

Extra information, such as Mudlet version, operating system and ideas for how to solve / implement:

Mudlet 3.13.0