Silence assorted GHC warnings

unused values in do block
extra imports
missing type signature
fix typo in comment
Allow building with GHC-7.8.3

allow process-1.2
Add type signatures for numeric literals
Fix more GHC warnings

- every Monad is Applicative
- discarded values in do block
- variable name shadowing
Merge pull request #1 from bergey/ghc-7.8

Build with GHC 7.8