Compiler: option to warn about unused variable
Runtime: prefix unused variable with underscore
Revert "Compiler: option to enable nodejs compatibility"

This reverts commit 38dd07fbdb1232734ed3b39b11503ce73356dcec.
Revert "Compiler: fix #160 ; Option to specify the name of the global .."

This reverts commit 15783f8838fd69df87babd9e35f8f66f0d9b077f.
Compiler: portable way to refert to the global object @vouillon