[samigo-team] Clean up 2.9 versions

[David Horwitz]

Hi All,

If there are no objections I will do the following clean up of versions 
in the Samigo project:

- Merge the following versions into 2.9.0:
    - all 2.90-rc & 2.90-b version
    - 2.9 [tentative]

- rename "2.9.x" to to "2.9.1 [tentative]" inline with common Sakai jira 
practice.

Any objections?

D