Refactor parsing of Pi/Dependent Type Signature expressions to improve
error reporting and reduce lookahead.
Restored "__pi_arg" to use UN instead of MN again (due to a test
failure).
Removed commented out code.
Fix erasure from data constructors.
Add a check for missed newtype optimisations.
Fix indentation.
Add Data.Erased to libs/base.
Add workaround for some non-trivial case-matches on detaggable data.
Add a regression test.
Remove trailing whitespace.
Fixed typo
IdrisDoc now merges documentation more robustly using less code.
Merge pull request #1105 from ahmadsalim/improvement/refactorpis

Improvement/refactorpis
Merge pull request #1106 from ziman/fix-dctor-erasure

Fix erasure from data constructors
Merge pull request #1107 from ziman/data-erased

Add Data.Erased to libs/base
Merge pull request #1112 from PhilipRasmussen/idrisdoc

IdrisDoc cleanups and Haddock additions
Tweak mergeNotunified

No need to add a problem if already equal