This restores the previously used "modern design" of the Windows native file open/save dialogs. Also make the dialogs resizable. Fixes #578.
Since both gcc and llvm use ^ to mark the position of the error now, monospace font seems to be a better default font for the message window to avoid the ^ character misalignment. Fixes #435.
This makes the command syntax consistent with other Geany ones and more native on Windows.
We want it disabled by default in 1.25 for everyone, but want to be able to get it back on by default later on when the UI is more polished. So we will need to have a way to tell whether the configuration comes from 1.25 and should be upgraded or was willfully disabled by the user in a later version. So, use a temporary setting name that defaults to disabled for 1.25 See #553.