Re-enable divConq3 test.
Merge pull request #141 from pjonsson/enable-divconq3-test

Re-enable divConq3 test.
Avoid silently filtering out some malformed calls to copy.
Whitespace.
Merge pull request #142 from pjonsson/robustify-deepcopy

Avoid silently filtering out some malformed calls to copy.
Add decodeType.
Merge pull request #143 from pjonsson/add-decodeType

Add decodeType.
Make feldspar-compiler a plugins-multistage client

With plugins-multistage it is now possible to use the `loadFun` from
`Feldspar.Compiler.Plugin` to dynamically compile and load Feldspar
functions into Haskell sessions.
Use explicit ghc
Lookup runtime header files in package databases or locally
Document the Marshal module
Remove debug printout
Refine comment
Add Marshal and Reference instances for tuples
Add an External Program parser with some tests.

This code allows us to inject test cases directly into feldspar-compiler
without having to coerce feldspar-language to generate the right thing.

The code is not perfect, but it does parse all gold files except divConq3
which uses futures. The current test suite does catch a lot of thinkos, so
it should be possible for others to improve the code without breaking things.
The type reconstruction for divConq3 can be done, but having some potential
extra test coverage seems better than waiting for perfect test coverage
indefinitely.
Add CRC benchmark

Benchmark the CRC implementation
 * Using the Feldspar evaluator
 * Using compiled code by loading it using plugins.
Add Default instance for Ptr and SA
Whitespace
Initialize (zero) memory allocated by initArray
Allow null pointers in freeArray