Fix wrong test: boolean variable is never negative

This has been spotted by clang++.
Reimplement inset-select-all in a generic way

There are 3 possible actions (in order)
* select current cell
* select all calls of inset
* select the inset from outside (in the containing inset)

This fixes completely #7727.
PDF-comment.lyx: reset style and some fixes

- the example was designed to follow the style of the other LyX documentation files, e.g. not to insert options as one big TeX-code inset.
- fix some typos
- (I cannot save files with LyX 2.2 atm due to bug #9234)
PDF-comment.lyx: store in format of LyX 2.2

 that works now with the proposed fix for bug #9234
Fix for bug #9234, from Georg.

Our TempFile class uses QTemporaryFile internally, and, on Windows,
this keeps the file locked so that we cannot rename it. So we have
to release the lock.
remove file that was accidentally committed
small tweaks spotted by Uwe
pdfcomment.module and PDF-comment.lyx: some minor tweaks

- use a uniform naming scheme and a style fix as discussed
Fix bug 9300. We need manually to convert newlines to paragraph breaks.

(cherry picked from commit 8f40d784c077e95f402c77b07f61c6f740ad67f1)
Fix bug #7970: space disappears from equation when reopening LyX file.
Fix bug #9319: Problems with space inside math and textrm.
InsetFootlike.cpp: disable listings inside footnotes

fixes bug #9321
Implement "callstack printing" checking for autotools

Contrary to cmake, we do not rely on platform/compiler check, but on the
availability of the reauired API.
graphicboxes.module: new module

support for the 4 boxes provided by the LateX package graphicx
cosmetics
sk.po: update
PDF-comment.lyx: remove unneeded preamble code