set isinteractive via the command line

Otherwise it looks like ~/.juliarc.jl will always be loaded too early
backwards compat
fix option passing
Merge pull request #230 from jkroso/fix/isinteractive

set isinteractive via the command line
Update Dict construction to reflect new syntax

Julia 0.4 changes the syntax for constructing Dicts; this commit changes
this package so that it uses the new syntax.