Initial version of inlinining externals. This version BREAKS WITH SERIALIZATION. Also it does not help much because of duplicate in PUSHCONSTARG.
temporarily disable unfinished externals inlining
Replacing distn2 by individual do_functions with .Call interface.
Replacing distn3 by individual do_functions with .Call interface.
Replacing distn4 by individual do_functions with .Call interface.
Replacing Random1 by individual do_functions with .Call interface.
Replacing Random2 by individual do_functions with .Call interface.
Replacing Random3 by individual do_functions with .Call interface.
Changing rmultinom from .External to .Call.
Changing rmultinom from .External to .Call (distn.R).
Faster dotcall (native calls) by avoiding repeated symbol lookup.
Typo in comment.
Fixed bug in accessing arguments through .Call.
Faster inherits (also makes .Call faster) via checking based on cached CHARSXPs.
Preserving selected CHARSXPs (a fix).
Inlining wrappers for native calls.
Merged changes from extinlining (inlining native calls and related optimizations) to master.