Trebuchet: Better layout for isScreenLarge devices

This change increase the space for the shortcuts at hotseat to fit the workspace on
isScreenLarge devices. Also deactivate and remove the stretch screen setting, because
the dimensions are always calculated on these devices. Also this change configures the
space between hotseat pages to avoid to display icons for other pages in the current
hotseat page.

Patchset 2: Added nebkat suggestions

Screenshots from TF700T:

Landscape -> https://sharecloud.ruesga.com/public.php?service=files&t=efede324ade05db79878eac13e637301
Portrait -> https://sharecloud.ruesga.com/public.php?service=files&t=79a7002a73e167eed08a195c4cf3d05c

Change-Id: I44e417ac42cec63ceb358977176ab536c8128f2b
JIRA: CYAN-502
Issue: https://jira.cyanogenmod.org/browse/CYAN-502
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>