phetsims/scenery-phet#52 change alignment 'bottom' to 'centerBottom' to be consistent with scenery layout values
phetsims/scenery-phet#52 handle i18n of plus sign on positive numbers
phetsims/scenery-phet#52 add @private annotations
phetsims/scenery-phet#52 change 'score' to 'points' throughout the interface and internal implementation, with the exception of the type name (that will be changed last)
add option to show '0' points, may be useful in some circumstances and easier to do it now
phetsims/scenery-phet#52 add 'rightCenter' alignment, used in many sims
phetsims/scenery-phet#52 remove erroneous options (fill, lineWidth) from PhetFont constructor
phetsims/scenery-phet#52 remove assumption that points >= zero, negative points now handled properly
phetsims/scenery-phet#52 change default option values to match the majority of use cases, instead of Balancing Act's requirements
phetsims/scenery-phet#52 fix more default options, replace option.pointsTextSize with option.pointsFont