Adds 2.11.0-M7 to 4.0.0-m1 section.

Remove 2.11.0-M5 section.
2.11.0-M7 blog post
Merge pull request #47 from scala-ide/staging/release-4.0.0-m1_2.11.0-M7

Update for 4.0.0-m1 on 2.11.0-M7