This fixes issue #5294.

There was a reuse of a gerror which lead to this crash. Freeing it after
using it once resolved the issue.
This change fixes #5294.

The live development didn't work if the path for the --user-data-dir (passed to Chrome(-ium) commandline didn't exist. Previously a path to /tmp/ ws constructed, but some users reported that this didn't work on their systems.
In order to fix this behavior, we now use the appSupportDirectory to store the user data directory.

The new location for the user-data-dir is now in ~/.config/Brackets/live-dev-profile.
To determine the location of the appSupportDirectory, the call to gtk_init had to be the first when the app starts. This will ensure that g_get_prgname() and g_get_config_dir() will return valid locations.
fixes https://github.com/adobe/brackets/issues/5327
Merge pull request #352 from adobe/jeff/fix-5327

Fixes Client 5327
* Implement Dark UI on Mac
Merge pull request #354 from adobe/jeff/dark-mac-shell

Into Darkness Mac
Don't use NSFileManager api for path existence detection in IsNetworkDrive api.
add a missing call to g_object_unref
Merge pull request #356 from eyelash/fixes

add a missing call to g_object_unref
Merge pull request #355 from adobe/rlim/mac-debug-issue

Don't use NSFileManager api for path existence detection in IsNetworkDrive api.
update cef
Merge pull request #357 from adobe/jeff/cef_3_1547_1459

Update CEF to 3.1547.1459
Merge pull request #342 from adobe/irichter/fix-5294

Irichter/fix 5294
Switch to file.openDroppedFiles command so that users can drop a folder as a new project.
Dark Mac with Full Screen Button
uncross hot to cold indicators on fullscreen button
Handle multiple files drop on top on Brackets shortcut on Windows.
Correct a logic error even though "nextQuoteIndex > 0" works when there is no quote since npos is a large positive number.
Merge pull request #361 from adobe/rlim/handle-dropped-folder

Allow folder drop on top of Brackets app.
Merge pull request #353 from eugeneo/folderdrag

[Mac] Accept folder dropped on shell icon