Index out of bound on sending incomplete request method
```
nim c -r tests/helloworld.nim
printf "G" | nc localhost 8080
```

Fails with
```
Listening on port 8080
/home/grfork/reps/httpbeast/src/httpbeast.nim(296) eventLoop
/home/grfork/reps/httpbeast/src/httpbeast.nim(203) processEvents
/home/grfork/reps/httpbeast/src/httpbeast.nim(115) slowHeadersCheck
/home/grfork/reps/httpbeast/src/httpbeast/parser.nim(10) parseHttpMethod
/home/grfork/.choosenim/toolchains/nim-1.4.0/lib/system/fatal.nim(49) sysFatal
Error: unhandled exception: index 1 not in 0 .. 0 [IndexDefect]
Error: execution of an external program failed: '/home/grfork/reps/httpbeast/tests/helloworld '
```