dump_otl.py fails if font contains size feature

[frankrolf]

The size feature is uncommon, but exists in Adobe’s static fonts, such as http://github.com/adobe-fonts/source-serif-pro/releases/latest . I noticed that dump_otl.py fails if this feature is present.

To fix the problem, I locally changed these lines to include a try/except statement.

before:

def dump_feature_record(feature_record):
    """Prints out feature records."""
    for index in range(len(feature_record)):
        record = feature_record[index]
        tag = record.FeatureTag
        feature = record.Feature
        print(index, tag, feature.LookupListIndex)
        if feature.FeatureParams is not None:
            print_indented("# name <%s>;" % feature.FeatureParams.UINameID)

after:

def dump_feature_record(feature_record):
    """Prints out feature records."""
    for index in range(len(feature_record)):
        record = feature_record[index]
        tag = record.FeatureTag
        feature = record.Feature
        print(index, tag, feature.LookupListIndex)
        if feature.FeatureParams is not None:
            try:
                print_indented("# name <%s>;" % feature.FeatureParams.UINameID)
            except AttributeError:
                pass

Please let me know if I should submit a PR with this change.