Duration and instant action handling in KB and plan parser

[m312z]

This PR includes an update to the KB to store and provide durative action duration inequalities, as well as a flag to note whether an action is an instant action. The PR will also include updates to the esterel plan parser to check this flag and not include vestigial action end nodes for instant actions.

[m312z]

I'll also go through these files to do a tab to space conversion...

[m312z]

Currently only parses the duration inequalities and sets instant action flag.