Indexing fixes

Merge pull request #24 from JuliaImages/teh/missing_indexing

Add linear indexing methods for ChannelView1

Fix typealias and IndexStyle depwarns

Merge pull request #22 from JuliaImages/teh/more_0.6depwarns

Fix typealias and IndexStyle depwarns on Julia 0.6

Fixes for Julia 0.6

Merge pull request #21 from JuliaImages/teh/0.6

Updates for new type system and tuple-printing