v0.7.8

DomainSets v0.7.8

Diff since v0.7.7

this is a bugfix release which fixes the hash of maps and an issue with mappings of VcatDomain

Merged pull requests:

• Use invoke function instead of macro (#156) (@jishnub)

Closed issues:

• VcatDomain(ℝ, ℕ) causes MethodError (#154)