Bump version number in dokku-installer.rb

Just bumping the version number to bring it up-to-date with the rest of the project.
update copyright year
Added option to set memory size for vagrant
Merge pull request #454 from dmyers/vagrant-memory

Added option to set memory size for vagrant
Merge pull request #443 from gdi2290/patch-1

update copyright year
Merge pull request #440 from imchairmanm/patch-1

Bump version number in dokku-installer.rb