Minor fix to SIRange show

The first element should be first, not the internal index from start
Make SIRange concrete for all Range types

This simplifies the definition of SIRange, allowing it to wrap all Range types as first class values. This improves inference on the range functions, for example:

Before
    julia> @code_typed(length(1s:0.1s:2s))
    1-element Array{Any,1}:
     :($(Expr(:lambda, {:r}, {{},{{:r,SIRange{Float64,0,0,1,0,0,0,0},0}},{}}, :(begin  # /Users/mbauman/.julia/v0.3/SIUnits/src/SIUnits.jl, line 44:
            return length(top(getfield)(r::SIRange{Float64,0,0,1,0,0,0,0},:val)::Range{Float64})
        end))))

After

    julia> @code_typed(length(1s:0.1s:2s))
    1-element Array{Any,1}:
     :($(Expr(:lambda, {:r}, {{},{{:r,SIRange{FloatRange{Float64},Float64,0,0,1,0,0,0,0},0}},{}}, :(begin  # /Users/mbauman/.julia/v0.3/SIUnits/src/SIUnits.jl, line 40:
            return top(box)(Int64,top(fpsiround)(Int64,top(getfield)(top(getfield)(r::SIRange{FloatRange{Float64},Float64,0,0,1,0,0,0,0},:val)::FloatRange{Float64},:len)::Float64))::Int64
        end::Int64))))

This removes the definition of `SIRange1` as it is no longer needed.  As it was neither tested or exported, I have not done anything to deprecate it.  I have kept the abstract `SIRanges`, even though it is no longer necessary or exported, to keep the interface stable.
Fix missing UnitRange for Julia 0.2
one(x) and zero(x) for x<:SIQuantity
Added versions for types
Merge pull request #30 from tlycken/identities

Multiplicative and addititive identities
Merge pull request #29 from mbauman/rangetype

Make SIRange concrete for all Range types
one(x::SIQuantity{T}) returns T
Merge pull request #34 from tlycken/identities

RFC: one(x::SIQuantity{T}) returns T
Merge pull request #26 from mbauman/rangeshow

Minor fix to SIRange show
Fix travis and coveralls badges

loladiro -> Keno
Promotion of identical SIQuantities shouldn't be concrete

The default fallback for `promote_type` in [Base](https://github.com/JuliaLang/julia/blob/3ddbaa1c03dd2fe0829c4c84f9b526d3d866c22f/base/promotion.jl#L101) assume that the promotion of two identical types is precisely that type itself.  Unfortunately, this is not true for SIQuantities, as they may be getting divided or multiplied and so we cannot infer the resulting type.  This is particularly important within array operations, where division of identical types previously resulted in the wrong type and multiplication threw a conversion error as this is used in the preallocation of the resulting array.

Fixes #27.
Merge pull request #35 from Keno/mb/promote-type

Promotion of identical SIQuantities shouldn't be concrete
Forward more Range methods to the wrapped SIRange

This allows SIRanges to be transformed with linear operators without becoming an array, just as typical Ranges do.
Merge pull request #36 from Keno/mb/range-forwards

Forward more Range methods to the wrapped SIRange
Fix Candela's superscripts in show

I suppose nobody is using inverse or square Candelas...

Also align the code block to make typos more obvious.
Merge branch 'master' into teh/dates

Conflicts:
	src/SIUnits.jl