Makefile: check for necessary versions of Ruby and Node
most files in script/ dir should be executable
clarify location and treatment of slow mocha tests
move common/interactive/controllers to common/controllers 

[#41923323], [#42157809]

The controllers themselves are the common category ... so
use 'controllers' as the top-level dir in common/
Makefile: simplify generation of source file lists
update rails backend to 3.2.11

[#42327381]