Use puppetlabs/git module for git package declaration

This commit remove git package resource declaration inside this module.
On Debian based system (Debian*, Ubuntu*), git-core is a meta-package on
git. This commit also solve the duplicate declaration faced by Andrew
in #114 (add rbenv support).

Compatibility is keept, but the git_package_name parameter is now
deprecated and has no effect.
[travis] Fix output formatter (for RSpec 3.0.0)
Force travis/spec to use RSPEC version 2.14.x

Since our test are not rspec 3.0.0 ready, we need to force travis
to use rspec version 2.14.x
Merge pull request #157 from sbadia/git-core

 Use puppetlabs/git module for git package declaration
Added support for company link and logo
Added description for company link and logo to the README
Rspec test for company logo and link
Merge pull request #160 from lschoepps/feature/company_logo_link

Added support for company link and logo
Fix for compatibility issue with exim, application.rb also needed to be
updated for 6.9
Added parameter description in init.pp
Parameter description for exim fix
Rspec test for exim fix
Merge pull request #159 from lschoepps/fix-exim

Fix for compatibility issue with exim
[doc] Fix dependencys list, Close #161, thanks @lieutdan13
[forge] Introduce metadata.json file (replacement for 3.6+)
[forge] Release version 0.1.5
Merge pull request #8 from sbadia/master

Upstream pull