Keep track of reporters in source order

The top-level dict, reporter_dict, in export.py is added to every time
the reporter decorator executes. Since the decorator executes when a
package is imported, this results in the addition of reporters to the
dict in source order. The dict has the name of modules as keys and the
keys index into a list of reporter functions. This eliminates the need
for the function collect_reporters, whose job it was to take a module
and find the reporters in it. It also obviates the need for the
is_reporter flag set in the decorator.
Added some style tags to the html report function