Minor formatting fix
Fix bug where use of :to-dir option with an existing directory does not generate an error
Handle :force option in ->files function
Update help text for -new- task
Fix executable test - add force option since test is being run in system temp directory
Create new tests for use of --force option
Merge pull request #1486 from mpblair/force-new

Add support for option to force execution of lein new when target directory already exists