Crash when luacheck is not available

[veger]

[Info  - 9:46:05 AM] coder inited
[Info  - 9:46:05 AM] extension initialize status: true
[Info  - 9:46:05 AM] loading STD library ...
[Info  - 9:46:05 AM] search /home/user/devel/my-project begin.
[Info  - 9:46:05 AM] loading /home/user/devel/my-project/file1.lua ...
[Info  - 9:46:05 AM] loading /home/user/devel/my-project/file2.lua ...
[Info  - 9:46:05 AM] loading /home/user/devel/my-project/file3.lua ...
[Info  - 9:46:06 AM] Connection to server got closed. Server will restart.
[Info  - 9:46:06 AM] coder inited

This happens a couple of times, until it gives up with

[Error - 9:46:09 AM] Connection to server got closed. Server will not be restarted.

When I installed luacheck, the crash is gone and the extension started to function properly.

I think it would be good to check if the tool is available and if not, issue a warning instead of crashing. This would help (new) users in figuring out what is going on.

[veger]

Nice, thanks!