+inve: first pass of subshell-style 'activate'
+inve.bat: (wip) ms windows subshell-style 'activate'

Can't believe I'm actually writing code to support friggin' Windows
users.
touch inve usage string a bit
implement 'inve' in python instead, easier to cross-platform

LOL I ain't writing no stinking Windows batch files. What was I
thinking?
one script to rule them all and in the darkness bind them
More spit + polish. Next: get rid of script-rewriting?
Update virtualenv.py and various scripts in embedded
bugfix etc