Simply some of the alignment calculations in heap_4.c to match those used in heap_5.c.

Simply some of the alignment calculations in heap_4.c to match those used in heap_5.c.
Remove some apparently obsolete code from xTaskPriorityDisinherit() (a task cannot be both blocked and giving bac a mutex at the same time].
Update the new "mutex held count" increment and decrement functions to allow mutexes to be created before the scheduler is started.

git-svn-id: https://svn.code.sf.net/p/freertos/code/trunk@2269 1d2547de-c912-0410-9cb9-b8ca96c0e9e2