COMPMID-556: Cherry-picked minor fixes from Github

- Added --api 21 to documentation
- Removed include of a runtime header in Core
- cherry-picked 2 small fixes from Github

commit 869d424d6fd5df7b15a858f2c5f853536f7a0aca
Author: giorgio-arena <arena.cpp@gmail.com>
Date:   Mon Oct 23 16:58:59 2017 +0100

    Update 00_introduction.dox

commit f054c210e493111061a458b887f7c4edaca06a9f
Author: Forrest Iandola <fiandola@gmail.com>
Date:   Mon Oct 16 00:44:24 2017 -0700

    fix comment

    typo
    kernerl's --> kernel's

Change-Id: I0a3893148a9565acbfd18d340da41845ce3ad44f
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/93460
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
3 files changed