Acquire bundled gems over SSL, ignore asset cache

Security tools not using secure protocols for dependencies
could be bad, use SSL to acquire gems, deter MITM.
Ignore the asset cache generated by rake assets:precompile.
application.html.erb: Make footer links open in new window

[Close #65]
Gemfile.lock: Switch to HTTPS
Found more external links and configured them to open in new windows

[Issue#65]
Gemfile: Switch to git instead of https
Reverted last commit
bundle update
Reverted change
Merge branch 'master' into experimental
Updated changelog
Updated version for experimental branch
Updated bundle
Gemfile: Updated  to use arachni 0.4.7
Bumped version number
Merge branch 'release/v0.4.4'