[Buildroot] [PATCH 0 of 4 for 2014.08] manual-text generation improvements

[Thomas De Schampheleire]

This patch series makes some improvements to the generation of the text
version of the manual:
- make sure that URLs are visible
- remove the 'logo' (logo.png) reference

To achieve this, two preparatory patches are needed.

Note that this series stands on its own, it can already be applied.
A subsequent series will make structural and content-wise changes to the
manual itself.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire at gmail.com>

---
Thomas De Schampheleire (4)
  gendoc infra: use $(pkgname) instead of explicitly passing 'manual'
  gendoc infra: add support for asciidoc configuration files
  manual-text: make sure URLs are displayed if a link text was provided
  manual-text: hide image representations

 docs/manual/asciidoc-text.conf |  19 +++++++++++++++++++
 docs/manual/manual.mk          |  26 ++++++++++++++++----------
 2 files changed, 35 insertions(+), 10 deletions(-)