Cmake build: Move default for man-pages to /usr/local/man

and at the same time make it configurable.
Until now it was hard wired to a subdirectory of installed lyx.
Cmake build tests: Make the tests for valid urls available to public

These tests already proved being valuable.
ia.po: updates from Giovanni
Remove diagnostic code that slipped in

I did not intend to commit this piece of diagnostic code
in a0f6b09a.
xyfigure, xypic: parser warnings and typesetting

This fixes several long "unusual contents found" warnings that
were being written from LyX's math parser and improves the
typesetting.

Thank you to Enrico for the fix. See here for his explanation:

http://www.mail-archive.com/lyx-devel@lists.lyx.org/msg180763.html

There are still two such warnings that might indeed be serious,
one each in fr/xypic.lyx and ja/xypic.lyx. I get an assertion
from cursor movement in those insets with instant preview enabled
(on both current trunk and branch).
Cmake build tests: Threadsafety and test-labeling

The tests are now more robust if ctest uses '-j' (number of threads) parameter.
a.) keytests are running in sequence and in one thread only, no other thread running
b.) tex2lyx tests are locking in respect to each other
c.) Test gets one or more labels, so that we can select
        ctest -L url
  to run tests labeled url
d.) New macro settestlabel() to add labels to a test
Cmake build tests: Label also layoyt tests
Typos
Add bindings for argument-insert
* Additional.lyx - next xdvi glitch spotted by Fabio.
* Additional: add note for okular.