implement inlineimport

[iK4tsu]

Achieves a lazier import style.

Features:

• import and use inline
• works with betterC
• custom error messages for better debugging

from:

Allows for a sequential import style with no extra syntax:

assert(from.std.algorithm.equals(from.std.algorithm.map!"a*a"([1, 2]), [2, 4]));

From:

Same as from, however it adds the ability to set the starting point of the module to check. Useful for betterC to bypass import std checks for example or to import core:

assert(From!"std.math".abs(-1) == 1);

I'm not sure about the naming of this feature inline import. Naming ideas are welcome.