Add a page that gives an overview of each repository component
Formatting and wording fixes
A few more small formatting fixes
Make line lengths <= 80 chars
Add top-level grouping sections
Note the corresponding Ant target(s) for each component
Remove description from OME ant targets

These targets are meant to be confusing. Removing description prevents them
from being listed in the output of `ant -p`
Homogeneize description of ant targets
Use lowercase for xsd-fu and specification
Merge pull request #1493 from melissalinkert/component-overview

Add a page that gives an overview of each repository component
Merge pull request #1498 from sbesson/ant_target_reviews

Ant target reviews