Key +/-:
name - official name of the activity package: this must be unique,
and determines the name of source and localization files.
wikiname - the name of your project on the OLPC wiki, such as Comic Maker.
description - long description of the activity and its audience
categories - any keywords that match your activity and its use.
see the activity grid for examples.
maintainers - you and others working on the activity, with links to
their userpages or ways to contact them.
license - the name of the license[s] your activity uses, with a link
to its full text.
status - from 0 to 6. 0:idea, 1:stub, 2:immature, 3:active development,
4:beta, 5:stable, 6:finishing touches
version - the version number of the latest build.
source-url - a raw url for the source repository .
builds - latest builds in which the activity has been tested.
mimetypes - mime types that the activity can read and launch.
comments - general comments about development.
l10n-notes - comments about localization.
