coq_HEAD: update to latest Git version

In particular, to get the fix for #3585 in the Coq bug tracker
pleasant ruby
some improvements
add libs to GEM_PATH
stop using gross dependency resolution
allow importGems to override cp args
include patches
correctly implement patching
further improvements to patches and build process
more gem improvements
terminal-notifier
ruby-dotenv
gem build updates
ruby updates
call patches with the right nix
reorder gem phases
patch logic
remove depsPath
update patch comments
inherit the correct rake in buildRubyGem

this avoids accidentally depending on Ruby 1.9.3's rake for *every* gem