(Refactor) Extract PapiRegionProfiling pass.

Separate it from the rest of the PAPI profiling facility.
(pprof) Prepare transition to JSON output

We change the signatures of the profiling functions to
move region resolving and timing export to the stack
object included in the pprof-study.

This way we are independent of the final number of counters
and we would be able to instrument object files without main
functions as well.
Fix PAPI instrumentation
Add a dummy profiling pass for caddy
Remove dead code
Enable Caddy before extracting SCoPs
Enable PAPI CScopProfiling.

We provide basic support for PAPI CScop profiling for now.
Functionality is shared with PapiRegionProfiling.

We do not require a PapiRegionPrepare pass. Instead of trying
to make that abomination work again, we should rely
on the FunctionCloner of polli instead.

In order to instrument without recompilation use the following flags
for polli:
  -instrument -caddy -no-recompilation

Do not forget to add the necessary libraries:
  -lpapi -lpprof

Support for building libpprof.so is required in the pprof-study.
Use a ModulePass to initialize PAPI & Profiling

Place a call to the papi_setup
and PAPI_library_init functions at the beginning
of the main function.
Use a stack to manage the eventIDs
Use a generic PassManager instead of a FunctionPassManager
OutputFilename support

Now we can use polli similar to opt (few bits are missing yet).
So far it should be possible to use polli within
the pprof-study, as a replacement for opt.
Support pprof-study
Pass argc & argc to libpprof
Don't assert when getSafeExit / getSafeEntry fail

Return a NULL ptr instead of failing an assertion.
We don't need to instrument everything.
Pass name of Exit block
Don't always run static constructors
Switch back to ScopDetection based instrumentation.

We can switch on algebraic support in the ScopDetection now, without
having to model the SCoPs with CScopInfo.
Support Profiling of SCoPs without SESE property

Instrument all incoming edges and exiting edges witht he same event id.
Support Jitable Scops profiling