Start eval routines. Based on carl chatfield and steve binet code.
Start to be able to handle nil properly
Don't use GNU readline or linenoise so we can use gub to debug this. Show type in return value, save return values
Start unary expresions
Correct string "+". start adding unary ops. More tests
github.com/rocky/ssa-interp/eval -> github.com/rocky/go-interactive
Move main.go -> demo/eval.go
Ooops forgot to add demo/eval.go
Merge branch 'master' of github.com:rocky/go-interactive

Conflicts:
	.gitignore
	demo/binaryexpr.go