1. Modified typecheck-decls to decrement the total-tccs counter when removing
   a TCC
2. Modified typecheck-decl to call regenerate-xref on a declaration that is
   already typechecked.
Fixed set-type-lhs-mapping, determine-best-mapping-lhs,
determine-best-mapping-lhs-resolutions,
determine-best-mapping-lhs-resolutions, and
determine-best-mapping-lhs-resolutions* to use the thinst in determining which
resolutions are valid
1. Modified typecheck-mapping-lhs to remove the compatible test on expr
   resolutions - need to wait till set-type.
2. Also modified the thres value to remove theory instances that are not
   visible.
Modified pvs-file-send-and-wait to add pvs: package in call to
write-to-temp-file.
Fixed subst-mod-params* (modname) to use the modinst actuals and dactuals if
appropriate
Modified free-params-res (t modname) to also go down the type,
and added free-params-res (type-decl modname) to not go down the type
(recursively).
Replaced, e.g., (theory *current-context*) with (current-theory)
Modified create-formulas (resolution) to not hash if there are any
decl-formals involved.
Merge branch 'master' of github.com:samowre/PVS