parsing IndexLoopExpr
desugar index-loop
Merge branch 'master' into loop

Conflicts:
	lib/core/collection.egi
update
Merge branch 'master' into loop
fix
update
add sample to index.egi
update
Merge branch 'loop' of github.com:egisatoshi/egison3 into loop
pattern constructor application to one argument
implement IndexedExpr of VarExpr
add comb sample
fix order of index-loop variables
multiple indices
update
Merge branch 'master' of github.com:egisatoshi/egison3 into loop
Merge branch 'loop'