Fix SDEI link in readme.rst

Update readme.rst for v1.5 release ...

Change-Id: Id9bd0c20a5af4f41269a51a675018dcc59e93f6c
Signed-off-by: Dan Handley <dan.handley@arm.com>

Update Arm TF references to TF-A ...

Update Arm Trusted Firmware references in the upstream documents to
Trusted Firmware-A (TF-A). This is for consistency with and
disambiguation from Trusted Firmware-M (TF-M).

Also update other Arm trademarks, e.g. ARM->Arm, ARMv8->Armv8-A.

Change-Id: I8bb0e18af29c6744eeea2dc6c08f2c10b20ede22
Signed-off-by: Dan Handley <dan.handley@arm.com>
Signed-off-by: David Cunado <david.cunado@arm.com>

Clarify third party license info in readme ...

Clarify the license information for imported third party code in
the readme.rst file.

Change-Id: I96e26fda687a290a6dffb475aca20b169d85784d
Signed-off-by: Dan Handley <dan.handley@arm.com>

Update readme for v1.4 release ...

Update the release notes (readme.rst) for the ARM Trusted Firmware v1.4 release.

Also, reorder and fix some of the links following the conversion to
reStructured text format.

Change-Id: I8f5e8aa86cb891f61b6b62cf9fab0ad0f0ebb36b
Signed-off-by: Dan Handley <dan.handley@arm.com>

Convert documentation to reStructuredText ...

Due to recent issues in the rendering of the documentation on GitHub and
some long-standing issues like the lack of automatic table of content in
Markdown, the documentation has been converted to reStructuredText.
Basic constructs looks pretty similar to Markdown.

Automatically convert GitHub markdown documentation to reStructuredText
using pandoc.

Change-Id: If20b695acedc6d1b49c8d9fb64efd6b6ba23f4a9
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>