Rename InstHead to InstRule and DeclOrInstHead to InstHead. Work on #31.
HLint fixes.

No functional changes. Mostly removing redundant parentheses/$.
Second round of HLint fixes.

No functional changes. Mostly removing redundant do/parentheses/$.
Push BangType down into Type. Groundwork for #11.
Introduce type equality constraint constructor
Fix ConstraintKinds tests

We now support type equality constraint
Add tests for the PackageImports extension.

Include positive (works when PackageImports is present) and negative
(compile error if PackageImports is absent) tests.
No code HSE code changes required to make these tests pass.
Test: use forward slash instead of a platform-specific. See #142
Type parser fix (type list cons) and test cases for it
Separate unknown pragmas from comments. Fixes #62.
Get the source location as the last member of the implict block. Fixes #5.
Add test case for #5.
Get the source location as the last member of implicit class blocks. Fixes #32.
Add test case for #32.
Test PolyKinds. Fixes #30.
Allow variable class assertions with constraint kinds. Fixes #107.
Add test case for #107.
Parse promoted lists in atype. Work on #108.
Remove a happy warning for an unused rule.
Merge stype with atype. Fixes #11.