Alec Thomas 581a3564ff Allow --enable, --enable-all and --fast to coexist.
This is useful to first enable all linters (including fast ones), then
only enable fast linters, then add extra linters. eg.

```
golangci-lint run --no-config --enable-all --fast --print-issued-lines=false \
    --exclude-use-default=false --tests --enable typecheck .
```
2018-06-09 19:49:24 +10:00
..