Attempt to convince Pkg to install on julia 1.0

Trying to fix this error:

ERROR: Unsatisfiable requirements detected for package ParticleFilters [c8b314e2]:
ParticleFilters [c8b314e2] log:
├─possible versions are: [0.0.1-0.0.3, 0.1.0-0.1.2, 0.2.0, 0.3.0] or uninstalled
├─restricted to versions 0.2.0-0.2 by an explicit requirement, leaving only versions 0.2.0
└─restricted by julia compatibility requirements to versions: 0.3.0 or uninstalled — no versions left

Refactor with greater support for non-POMDPs models

The biggest change is to replace SimpleParticleFilter with BasicParticleFilter and split the update into 3 specific steps that can all be individually modified.

Also added ParticleFilterModel to make construction of models without POMDPs more straightforward.

Compatibility with Julia v1.0

[WIP] Fixes for 0.7 (#14)

* fixes :cat:

* missed some deps

* modernize tests

* more fixes, tests are breaking

* tests working

* updated travis to use 0.7 and 1.0

Added POMDPToolbox dependency, moved obs_weight

• added dependency on POMDPToolbox
• obs_weight was moved to POMDPToolbox
• added specific method to work with alpha vector policies

Added UnweightedParticleFilter, fixed sampletype

Merge pull request #7 from JuliaPOMDP/unweighted

added unweighted

Update to reflect changes in StatsBase

There was some code to support arbitrary RNGs with weight vector sampling, but now this is in StatsBase (JuliaStats/StatsBase.jl#245)

Added obs_weight default implementations

v0.0.2

added obs_weight