- Make this for CCLS to be happy
- Include this "precompiled header" everywhere
- Make includes from the src folder, and leave all ambiguity

- Correct minimal version
- Correct message status

- The message no longer outlives the logger
- Update the objects that use the LOG API
- Print more things with the stderr dispatcher
- The UI, src/Lib, src/Lib/Ass, src/Lib/Document use the new LOG API

- Disable the subobject linkage warning for gcc.
- Solves one shadowing pb
- Delete unused DataPtr

BUILD: Only place external headers in the precompiled header to avoid recompiling it every time a local header is changed

Also fix all the warnings present with clang and get ride of most of the
forward definitions when possible.

For it to be easy to use, just unpack the 1M source files in a vendor
folder for all third party's libraries

BUILD: Add CONFIGURE_DEPENDS to let cmake reconfigure if new files where added to the project (or removed)

Two main folders: Lib and UI. The Lib is specialized in Document and
Ass, the UI is specialized for private DocumentViews (private document
views) and others (future ScriptViews, etc)

TODO: Open a new tab with the properties instead of a new window

DOCUMENT & MISC: Add the AudioContext to the AudioSubDocument and create the Lib folder to store all the code that is not a UI code but can be included by all other src's sub-folders

BUILD: Use precompiled headers, store all forward declarations in the "Utils.hh" header and use namespaces to isolate vivy's code

If a debug build is needed, use the following invocation of cmake:
    cmake -Bbuild -DCMAKE_BUILD_TYPE=Debug

Where:
* -B stands for the build folder
* -DCMAKE_BUILD_TYPE stands for the release type (Debug or Release)

Put clang and CXX specific flags only in those cases

Removing icon for the moment

CMP0100 is set to NEW, so moc and uic can be run on .hh files if needed.
This is the new behaviour of the policy so it's safe. It also permits to
separate clearly C++ headers from C ones.