LALPulsar: check for SIMD extensions

- add M4 macros from Autoconf Archive
- check for architecture flag, MMX/SSE/AVX extensions, -mfpmath flag
- refs #1000, #358
LALApps: add lalapps_ComputeFStatistic_v2_SSE to default build

- so that running "make" will check if LocalComputeFstat.c is compilable
- refs #1000
ComputeFStatistic_v2: remove --GPUready option and related code

- refs #1000
HierarchicalSearch: remove --GPUready option and related code

- refs #1000
ComputeFStatistic_v2: remove --upsampleSFTs option and related code

- refs #1000
HierarchicalSearch: remove --sftUpsampling option and related code

- refs #1000
RecalcHSCandidates: remove --sftUpsampling option and related code

- refs #1000
HierarchSearchGCT: remove --sftUpsampling option and related code

- refs #1000
LALPulsar: move ComputeFstat.[ch] to ComputeFstat_OldDemodAPI.[ch]

- move documentation from ComputeFstat_h to ComputeFstatDemod_h
- new ComputeFstat.h just includes ComputeFstatDemod.h for now
- refs #1000
ComputeFstat: unified API for computing the F-statistic

- ComputeFstat.h defines the API
- ComputeFstat.c will implement common API code
- ComputeFstat_Demod.c will implement demodulation
- ComputeFstat_Resamp.c will implement resampling
- Modify LALInference and LALApps configure.ac to check for
  XLALComputeFstat() when linking against LALPulsar
- refs #1000, #534
ComputeFstat: implement SetupFstat_Common()

- performs basic sanity checks on common input data
- allocates FstatInputData* struct
- refs #1000
ComputeFstat: implement XLALComputeFstat()

- allocates memory, then delegates to internal algorithm-specific
  functions to compute F-statistic
- also implemented FstatResults destructor function
- refs #1000
ComputeFstat_Demod: implement XLALSetupFstat_Demod() and ComputeFstat_Demod()

- XLALSetupFstat_Demod() sets up demod data and buffers
- ComputeFstat_Demod() calls the LAL ComputeFstat() function in a loop
- also implement FstatInputData_Demod, and its destructor function
- refs #1000
Move ComputeFstat_RS.[ch] and Fstat_v3.[ch] to LALPulsar

- rename ComputeFstat_RS.[ch] to ComputeFstat_OldResampAPI.[ch]
- rename Fstat_v3.[ch] to LFTandTSutils.[ch]
- rename testFstat_v3.c to TestLFTandTSutils.c, add to LALPulsar tests
- for SWIG, add struct tagnames and comment out undefined functions
- prevent ComputeFstat_OldResampAPI.h from being included in
  ComputeFStatistic_resamp.c due to conflicting types
- refs #1000
ComputeFstat_Resamp: implement XLALSetupFstat_Resamp() and ComputeFstat_Resamp()

- XLALSetupFstat_Demod() sets up demod data and buffers
- ComputeFstat_Demod() calls the LAL ComputeFstatFreqBand_RS() function
- also implement FstatInputData_Demod, and its destructor function
- refs #1000
ComputeFstat_Resamp: use demodulation to compute F-stats for a single frequency

- resampling algorithm is currently too slow to be practical for e.g.
  recalculating top-list F-stats in the GCT code
- use fixed Dterms=8 for demodulation, compatible with optimised code
- print a warning the first time the demodulation code is called
- refs #1000
LALPulsar: XLALify LALExtrapolatePulsarPhase()

- refs #1000
LALPulsar: move XLALifed LALEstimatePulsarAmplitudeParams() to ComputeFstat

- refs #1000
ComputeFStatistic_v2: port to unified F-stat API

- and use correct LAL error codes
- refs #1000
HierarchSearchGCT, LineVeto, RecalcHSCandidates: port to unified F-stat API

- disable RecalcHSCandidates command-line option --useFstatWeights, since API
  does not (currently) support turning on/off noise weights when calling
  XLALComputeFstat(), as would be required to support this option
- refs #1000