Use SparseTabularMDP from POMDPModelTools

[MaximeBouton]

• Use SparseTabularMDP
• solve methods only for MDP

TODO: add a warning for POMDPs?

[MaximeBouton]

Restart travis after JuliaRegistries/General#2643 gets merged

[MaximeBouton]

The build fails in 0.7, I think we can safely drop the support.
Any objections @zsunberg @rejuvyesh ?

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@95f407d). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master      #32   +/-   ##
=========================================
  Coverage          ?   97.72%           
=========================================
  Files             ?        4           
  Lines             ?      132           
  Branches          ?        0           
=========================================
  Hits              ?      129           
  Misses            ?        3           
  Partials          ?        0

Impacted Files	Coverage Δ
src/sparse.jl	90.9% <100%> (ø)
src/vanilla.jl	100% <100%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@95f407d). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master      #32   +/-   ##
=========================================
  Coverage          ?   97.72%           
=========================================
  Files             ?        4           
  Lines             ?      132           
  Branches          ?        0           
=========================================
  Hits              ?      129           
  Misses            ?        3           
  Partials          ?        0

Impacted Files	Coverage Δ
src/sparse.jl	90.9% <100%> (ø)
src/vanilla.jl	100% <100%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 95f407d...e739781. Read the comment docs.

[mykelk]

Sounds good to me.

[zsunberg]

The build fails in 0.7, I think we can safely drop the support.
Any objections @zsunberg @rejuvyesh ?

drop it!