Removed doc files (Doxygen autogens them), added LFSR, changed structure.
- Doc files can be automatically generated by doxygen. They never should have
  made it into the repository.
- Package files are now co-located in the directory of files they rely upon.
  This causes the makefiles to be more readable and simplifies the structure a
  bit.
- Added LFSR. Galois and Direct architectures both added.
- Added Vendor package. Currently only have one for Xilinx. When using optimized
  structures, use the vendor package to abstract out the vendor-specific forms
  of a complex multiply, direct multiply, PLL, etc.
- Started work on Xilinx-optimal complex multiplier.