Array slice

[Creepsky]

Add an built in array slicing method.
A slice has this type: identifier [&] identifier
A slice literal has this format: expression[range literal]

Idea:

i32 [] test;
i32 var1 = test[0]; // element 0
i32 [&] vars = test[0..5]; // elements 0 to 4
i32 [&] vars = test[..]; // all elements
i32 [&] vars = test[..5]; // elements 0 to 4
i32 [&] vars = test[5..]; // elements 5 to end