Improve efficiency and behaviour of vListInsertEnd().

git-svn-id: https://freertos.svn.sourceforge.net/svnroot/freertos/trunk@1951 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
Add Newlib reent support.

git-svn-id: https://freertos.svn.sourceforge.net/svnroot/freertos/trunk@1952 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
Merge remote-tracking branch 'trunk'