Automatically handle situations when .flora directory doesn't exists

[dm3ch]

I've got two errors

1. This error appeared cause ~/.flora hasn't been existed.

2019/07/08 00:39:13 Downloading Terraform 0.7.0
2019/07/08 00:39:13 open /Users/dmitry.chepurovskiy/.flora/terraform_0.7.0.zip: no such file or directory
exit status 1

2. This error appeared cause ~/.flora/bin hasn't been existed.

2019/07/08 00:43:59 Adding symlink /Users/dmitry.chepurovskiy/.flora/terraform_0.7.13->/Users/dmitry.chepurovskiy/.flora/bin/terraform
2019/07/08 00:43:59 symlink /Users/dmitry.chepurovskiy/.flora/terraform_0.7.13 /Users/dmitry.chepurovskiy/.flora/bin/terraform: no such file or directory

It would be a good improvement for my opinion if we would create this directories while flora execution.