Log Message:
Update lang/coq to 8.2pl2

As camlp5 is required with ocaml 3.10, bring it as a dependency anyway,
instead of requiring ocaml 3.10

Changes include:
* Installation
- Support for compilation with ocaml 3.10 and (transitional) camlp5.
- Many bugs have been fixed (cf coq-bugs web page)
- All known failures of ROmega have been fixed. It should now be a
  faithful and quicker replacement for Omega (except when nat parts
  are involved). ROmega and Omega now handle <->.
- Better computational behavior of some constants (eq_nat_dec and
  le_lt_dec more efficient, Z_lt_le_dec and Positive_as_OT.compare
  transparent) [exceptionally source of incompatibilities].
- Loading FSets/FMap used to open unwanted scopes of integer datatypes
  (see bug #1347). These scopes may need to be manually opened now.