DFL64 rev.2

[qchikara]

Win64 support

Note: This depends on #49 COFF Format Support.

Goal

1. Minimal patches.
2. No breaking change to win32 programs.

Limitations

1. Win64-support by DMD requires MS Visual Studio and Windows SDK.
2. dfl.socket and dfl.registry are NOT supported ths time. ( ignored by "version (Win64) {...}" )

Fix compile error

Fix Dozens of size_t conversion error.

Add toI32 helper function instead of type cast.

Especially, collection helpers are rather complicated.

Fix runtime error

Update WIn32 APIs

1. SetWindowLong family. SetWindowLong -> SetWindowLongPtr, and so on.
2. Common dialogs: structures and callbacks. UINT -> UINT_PTR, and so on.
3. Windows timer functions: callbacks.

Fix application manifest

embedded in dfl/application.d.

Split off Toolchain update

See #49

[qchikara]

appended a small fix of the richtextbox.

Though these all needs modified against the 2.070 druntime which brings full Win32 APIs and conflicts...