Add missing #pragma once + missing include
* speeds up incremental builds as changes to a header will not always
need the full mocs_compilation.cpp for all the target's headers rebuild,
while having a moc file sourced into a source file only adds minor
extra costs, due to small own code and the used headers usually
already covered by the source file, being for the same class/struct
* seems to not slow down clean builds, due to empty mocs_compilation.cpp
resulting in those quickly processed, while the minor extra cost of the
sourced moc files does not outweigh that in summary.
Measured times actually improved by some percent points.
(ideally CMake would just skip empty mocs_compilation.cpp & its object
file one day)
* enables compiler to see all methods of a class in same compilation unit
to do some sanity checks
* potentially more inlining in general, due to more in the compilation unit
* allows to keep using more forward declarations in the header, as with the
moc code being sourced into the cpp file there definitions can be ensured
and often are already for the needs of the normal class methods
This move the finding of links and the creation of a `linkpreviewer` into c++.
- The links are now extracted from the text in `texthandler`
- The `messageeventmodel` now creates and stores `linkpreviewers` for events that have links in the current room.
Two new model roles have been created to let a text delegate know when the link preview should be shown (`showLinkPreview`) and pass the link previewer (`linkPreviewer`). Empty link previewer are returned where link don't exist so the qml doesn't have to have checks for whether the parameters are undefined.
Uses Matrix's preview API to generate embedded link previews.
Only title and description for now.
