Tag 1.0

[dlfivefifty]

I think now that the more experimental lazy-banded matrix support has been moved out the API should be pretty stable. Some possible changes we might want to make first:

1. Rename brand. Actually, I might just move this out into LazyBandedMatrices.jl since its mostly used for testing. I'm thinking a better syntax may be BandedMatrix(Rand(10,10), (1,1)) where Rand corresponds to a lazy random matrix.
2. Rename _BandedMatrix. The logic on this name is to distinguish from BandedMatrix(::AbstractMatrix) which converts a general matrix to be banded, and that the details of storage is an "implementation" detail.