v0.6.4

SumOfSquares v0.6.4

Diff since v0.6.3

Merged pull requests:

• Univariate minimization example (#263) (@blegat)
• Add chebyshev basis to univariate example (#264) (@blegat)
• Add explanation on Gram basis for Chebyshev basis (#266) (@blegat)
• Update talks (#268) (@blegat)
• Add polynomial optimization example (#271) (@blegat)
• Add Julia Set example (#272) (@blegat)
• Update link to list of solvers (#273) (@blegat)
• Add quadrotor example (#274) (@blegat)
• Add polar approach to quadrotor tutorial (#275) (@blegat)
• Fix printing with latest version of JuMP (#276) (@blegat)
• Add test/Project.toml (#277) (@blegat)
• Fix Sparse.Putinar with Newton polytope (#278) (@blegat)
• Use import as syntax (#280) (@blegat)
• Add format action (#281) (@blegat)