Fix reset to BL3-1 instructions in user guide, part 2

Fix the instructions for resetting to the BL3-1 entrypoint in the
user guide. The BL3-1 and BL3-2 image locations changed in the fix
to ARM-software/tf-issues#100 (commit 186c1d4). This is distinct
from the similar issue fixed in commit bfb1dd5.

Also clarify the dependence on the FVP_SHARED_DATA_LOCATION and
FVP_TSP_RAM_LOCATION build options, and tidy up the "Notes
regarding Base FVP configuration options" section.

Change-Id: I6b03452a71f0c69efa169852712bcb184242696e
Add Juno instructions to user guide

This patch makes the Trusted Firmware build instructions in the
user guide platform independent.

FVP specific instructions have been grouped together under a new
section dedicated to FVP.

Juno specific instructions to build and run the Trusted Firmware,
UEFI and Linux have been added.

Change-Id: I9bfb1b9d732b1f73abbe29f68ac931e1773a4fd5
Merge pull request #201 from danh-arm/jc/juno-user-guide

Add Juno instructions to user guide
Merge pull request #200 from danh-arm/dh/fix-reset-to-bl31-part2

Fix reset to BL3-1 instructions in user guide, part 2
Add information about Juno in firmware-design.md

This patch reorganizes the firmware design guide to add information about the
port of the ARM Trusted Firmware to the Juno ARM development platform.

Change-Id: I0b80e2e7a35ccad1af2e971506cfb7fe505f8b84
Merge pull request #202 from achingupta/ag/fw-design-juno-update

Add information about Juno in firmware-design.md
Miscellaneous documentation fixes

This patch gathers miscellaneous minor fixes to the documentation, and comments
in the source code.

Change-Id: I631e3dda5abafa2d90f464edaee069a1e58b751b
Co-Authored-By: Soby Mathew <soby.mathew@arm.com>
Co-Authored-By: Dan Handley <dan.handley@arm.com>
Merge pull request #203 from danh-arm/dh/misc-docs-1.0

Miscellaneous documentation fixes