Add and revert 64 bit integer script conversions

[elexis]

Whenever one tries to send a variable of the type i64 (std::time_t) or u64from C++ to JS, the code compiles on linux but not on windows (happened with #3258 and r17928). The replay list currently convert the timestamp to a string and should be fixed. At that time, Itms added a change to source/scriptinterface/ScriptConversions.cpp so that the code compiles on windows, but that doesn't work on unix, see attachment:t3258_visual_replay_menu_v9.2.patch:ticket:3258​.

[elexis]

A patch that had been proposed before (but doesn't compile on linux iirc).

[echotangoecho]

Patch which may or may not work on windows.

[echotangoecho]

Additional note: the type of std::time_t is undefined.

[Stan]

I'll try it tomorow evening. If nobody does before then. What should I look for

[echotangoecho]

If it doesn't work, you will get compiler errors.

[Stan]

Compiles fine on W10 64bits MSVC 120_XP Debug + Release modes. Game launches afterwards.

[echotangoecho]

Add tests (just adapted the i32 and u32 conversions tests).

[elexis]

(21:13:12) Philip: Whoever was looking at 64-bit stuff: make sure you test it on 32-bit Linux too, because that's different to 32-bit Windows

[Itms]

In 19189:

Fix 64-bit integer script conversions by removing the discrepancy between Windows and Linux.

Patch by echotangoecho, fixes #3848.
Reviewed By: Itms

Differential Revision: ​https://code.wildfiregames.com/D84

[elexis]

In 19367:

Revert 64bit number conversions added in r19189, don't add the previous long and unsigned long conversions back and use double in the Replay menu.

64bit conversions (including the long ones) are not safe, because not every number can be converted to the 2^{53 JS numbers and pretending to do so is asking for bugs.
Explicitly use the double type in the Replay menu, because std::time_t is unspecified and some platforms like Ubuntu yakkety:i386 fail to build, looking for long.
Double should work for the next 285 million years, becomes consistent with SavedGame.cpp, is tested by test_ScriptConversions.cpp and doesn't pretend to cover all 64bit numbers.}

Patch By: echotangoecho
Differential Revision: ​https://code.wildfiregames.com/D205
Refs #3848 D84 D112