Introduced DomainTheoryData and Precondition classes, re-structured classes to better support execution (in progress)
LPSFileManager updates domainTheoryData
Resetting fields for CanvasController and ExecutionManager improved (drawing invokes reset of fields), removed redundant 'isReady' in Token
database change results in a change in status for candidate tokens (change colours)
nodes are highlighted with corresponding tokens
Pressing 'Next' button now proceeds with next entity in line (currently does not check anything against DB).