Bump the patch version for a new release

Update the Changelog reflecting the drop of GHC 7.10 support

Bump the package version to 0.3.8

Bump upper bound of ghc-prim

Merge pull request #56 from composewell/maint

Minor maintenance updates to be included in 0.3.7.1

Use cabal build for ghc-7.10.3

bump version to 0.3.6

Fix appveyor badge URL

bump version

Bump version, update changelog