Merge pull request #23 from jerro/master

Aliases for 64 bit and 256 bit vectors in core.simd
Remove va_arg template in core.vararg.
Remove extern forward declarations fron d-bi-attrs - fix header includes in d-builtins.
Some more coding convention fixes... get started on code documentation for each function.
Carefully add overload for 'double' types to real_t implementation.  Should be enough to allow the removal of all these isConstX functions.
Remove special casing around DotTypeExp::toElem - implement the function in glue.
Compile fix
Merge pull request #24 from s-ludwig/patch-1

Compile fix
Fix ICE in hwi2toli
Implement longdouble in GDC, merge D frontend code affected.
More documentation, removal of some dead code.
Move 'convert' into IRState.
Remove 'needs_temp' - cleaner implementation in isFreeOfSideEffects.
Rename D RT libraries to match DMD ABI, move generation of internal library symbols from frontend to glue.
Pass stack frame between functions in the same way closures are passed.
Built-in GCC library functions now recognised by keyword unless -fno-builtin, remove aliases from libdruntime.  Rename __builtin_Clong to __builtin_clong.
Call _adEq2 for array equality comparisons, convert static arrays to dynamic in identity comparisons.
Clean-up va_start/va_arg implementation. Implement two new va_arg functions (one compiler, one runtime).
Update D Frontend to 2.060
Sync implementations of doFormat with upstream phobos.