- WITH-FOREIGN-OBJECT should eval the type parameter. Fixed this
  as well as the examples and tests that assumed it wasn't evaluated.
- document WITH-FOREIGN-OBJECT in the manual.
- removed the pseudo ability to specialize arguments on
  define-type-translator. That didn't quite work, doh.
- removed dead code from cffi-uffi-compat::foreign-type-size
  specialized on the uffi-array-type.
- uffi-compat: parse (:array <type>) as (:array <type> 1)
- uffi-compat: reflect the fact that CFFI:WITH-FOREIGN-OBJECT now
  evaluates the type parameter.

- Make the defcunion slots' count option be a keyword
like defcstruct. Fix the related docs and tests.

- New tests: tests/enums.lisp (4 tests) and tests/misc-types.lisp (3 tests).
- New file: objects.lisp, skeleton of the safe typed pointer interface. I
  also added a :boolean type here, it's looking for a better home still.
- (early-types.lisp): type parsers, DEFINE-TYPE-SPEC-PARSER and PARSE-TYPE.
  Added abbility to have anonymous types (ie. a name is no longer required
  for FOREIGN-TYPE). Moved DEFCTYPE to types.lisp.
- (enum.lisp): improved DEFCENUM, the values for each keyword are now
  optional, like in C. Added the anonymous type (:enum ...)
- (types.lisp):
    - Renamed :TO-C-ARG to :TO-C-DYNAMIC.
    - Renamed FOREIGN-AREF to MEM-AREF and implemented compiler macros
      for it.
    - New exported macro: DEFINE-FOREIGN-TYPE for parameterized types.
    - Change DEFINE-TYPE-TRANSLATOR back to the previous interface,
      translators take a type argument now and we have translators
      available at runtime now too.
    - FOREIGN-TYPEDEF's now inherit their parent type's translators.
    - New :wrapper type, for anonymous typedefs with translators.
- (strings.lisp): Renamed string to :string. Added new type, :string+ptr.
- (utils.lisp): renamed let-if to bif.
- (tests/callbacks.lisp): two tests were not being run for SBCL
  because I thought it triggered a bug but it's actually only one that
  triggers the bug. Fixed that.
- Updated examples and tests to use :string instead of string.