allow writing of adsorbate snapshots and density grids

• allow writing .xyz files of adsorbate positions during a GCMC simulation
• allow keeping track of grid recording spatial probability density of adsorbates during the GCMC simulation

fix grid test

runs on Julia v1.1

docs set up

We now have documentation.
https://simonensemble.github.io/PorousMaterials.jl/latest/

added grid functionality to look at accessibility of energy grids

• now perform flood-fill of potential energy grid, look at connections between segments, and block out inaccessible pockets
• during henry coefficient calcs (widom insertions), declare energy as Inf where we hit an inaccessible pocket to effectively block these during the simulation

Significant speed improvements

Both Molecule's and Framework's are now both composed of:

struct Atoms
    n_atoms::Int
    species::Array{Symbol, 1}
    xf::Array{Float64, 2}
end

and

struct Charges
    n_charges::Int
    q::Array{Float64, 1}
    xf::Array{Float64, 2}
end

Storing the coordinates and charges contiguously in memory allowed for some significant speed improvements in both the vdw and electrostatic energy computations, and, thus, simulations.

PorousMaterials.jl official first release but for Zenodo

Zenodo needs a new release...

PorousMaterials.jl official first release

The next release will be compatible with Julia 1.0.