[kde-doc-english] New online doc generation engine, reprise

[Luigi Toscano]

Hi again,
I spent a bit of time restructuring the code so that the generation is not
executed in the same directory: one directory for the checkout, one directory
for the new website which replaces the current website only if the generation
is successful; up-to-date files are copied from the old site. This simplifies
the checkout process (no need to check for spurious files) and the structure
of the output site (which contains only web-related files).
Also: documentation which has no English version is ignored; previously
missing modules are now enabled (Frameworks and extragear-edu); more
user-friendly search of an application doc given the application name.

For more details about the code changes, please check the history of the
dev/flexgenerator branch:

http://quickgit.kde.org/?p=websites%2Fdocs-kde-org.git&a=shortlog&h=f0d55fd52759af323c1fa5a17d05b7b96a540996

I regenerated the site again on the staging server, please check if you see
something strange:

http://docs-staging.kde.org

For the record, the complete regeneration ("cold") took 12.5 hours. The update
today took <~1.5 hour, mostly spent in English documentation which is always
regenerated (as timestamps returned by populate_documentation.sh are always
"fresh").

Known issues:
- the search part needs some fixes and probably a completely new engine
- the already mentioned issues with TeXLive 2015 are still there, so "es" and
"fr" have no PDFs at all; some "lt", "ru" and "tr" documents shows the issues
as well. This is unrelated from the code changes.

If no other major issues are popping out, I will merge the branch in master
and start updating the official site.

As already mentioned, volunteers for an overhaul of the site graphics are welcome!

Ciao
-- 
Luigi