Added --host option to define fontello instance url.
Fix for no host.
Remove .idea from .gitignore
* IntelliJ IDEA users can ignore this via their local gitconfig.
Fix grammar in documentation for host option.
Clean up addition of host option.
* Return session URL from API POST requests to allows a single place to fall
  back to the default host.
* Use host option instead of default host constant in one place.
Build.
Update version number.