Expose `atan2` for Ivory types.
ivory-strings: fixes:
  - use ixrep as the type (for now)
  - fail on initialize/store for HS strings that are too long
  - add a store lib function
concrete syntax: allow macros for struct initializers.
Nat API: try to make consistent between 7.8.3 and 7.6.
ivory-backend-c: change options parser datatype

- more flexible to keep both errors and successful parses around,
  and decide what to do with them later
- makes it easier to write the more general parser used by tower, etc
ivory-stdlib: fix typelit API usage.
type-lit api: back out unnec. changes from commit ac0d5.
ivory: increment version number because sourceDep was a breaking change

caught this a little late i know
travis-ci: get cvc4 from one day ago.
travis-ci: fix script
travis-ci: use gnu date format.
Allow serialization instances for arbitrary areas.
add Pat's RingBuffer as a test-case
Update RingBuffer.hs
better handling of procs
fix bug in interprocedural points-to analysis
found a bug(-ish) in the RingBuffer.

`RingBuffer n a` (arguably) should store n items, but can only store n-1
because it needs one extra slot for bookkeeping. (Arguably) we should
use GHC.TypeLits to make `insert` and `remove` have type `Ix (n+1)`.
ivory-model-check: can't assume memareas will have their initial value....
sigh, apparently KnownNat doesn't exist in ghc763
add Ivory.Opts.SanityCheck

checks for use of unbound or ill-typed functions/mem-areas.