get-key-blocking accepts optional interval/timeout

This is implemented by a shared function block-on in lanterna.common.
Document get-key-blocking optional args
No more get-key-blocking &rest map args

Looking back over the library, I realized that &rest args aren't really
used with maps anywhere else, so it doesn't make sense to use them here.
Adds remove-resize-listener
Makes block-on options map optional
Standardize documentation style
Use pos? instead of > 0
Bump version, fix arglist, document new stuff.