File.exists? is deprecated
Merge pull request #2738 from deivid-rodriguez/patch-1

File.exists? is deprecated
fix _prisitne_command, update ec5e102990bcbdf5d541fdf164d22dfb99684aec, update #2684
Merge branch 'master' of github.com:wayneeseguin/rvm
Add --default usage explanation in help for use command.
Merge pull request #2739 from marr/patch-1

Add --default usage explanation in help for use command.