Merge pull request #228 from ragerdl/master

Pull request from Rager's personal fork with a couple changes
WIP on parsetree
unfinished work on parsing generate blocks
added parser for generate stmts and integrated it with modules
Minor VL updates for SystemVerilog

  - Add support for SystemVerilog extensions to #(...) style parameter lists
    and some basic systests for these new constructs.

  - Enable support for unique, unique0, and priority case statements (with a
    warning that we don't implement the checks).
work on parsing interfaces
Merge remote-tracking branch 'remotes/origin/master' into generate

Conflicts:
	books/centaur/vl/loader/parser/modules.lisp
parser tests working, although none yet written for generate, modports, interfaces
fix json support (as yet incomplete for generate stuff)
fix ports problem
VL: Add support for parsing SystemVerilog interfaces and generate blocks.
(Merge to complete feature branch.)
Disabledp accepts runic abbreviations such as (:d append).  Added bin/ scripts to help ensure "purity" of ACL2 sources.

Quoting :doc note-7-0:

  The utility [disabledp] now accepts runic abbreviations such as (:d
  append). (See [theories] for a discussion of runic abbreviations.)
  Thanks to Shilpi Goel for requesting this enhancement.

Added preliminary scripts bin/purity.sh and bin/pull.sh to help ensure
"purity", i.e., that only ACL2 authors write to other than books/.
Thanks to many people for helping me with git (David, Jared, Keshav,
Shilpi, Sol).

Added/updated some .gitignore files.
Added cleaning of some generated files from books/workshops/2003/kaufmann/support/rtl/.
Updated doc.lisp to match books/system/doc/acl2-doc.lisp.  Also added generated files to doc/.gitignore.