patterns/includes: Update standard library and patterns to support the new bitfields (#102)

* Add `current_bit_offset()` and `read_bits(...)` to `std::mem`

* Replace deprecated BitfieldOrder enum values with new clearer names

This adds new options named `MostToLeastSignificant` and `LeastToMostSignificant` to replace the old `LeftToRight` and `RightToLeft` names. These names should be much clearer about what they affect and how.

* Throw errors when `std::core::(get|set)_bitfield_order()` are called

* Update all patterns to work with the new bitfield behaviors

patterns/spirv.hexpat

@@ -1,3 +1,5 @@
+#include <std/mem.pat>
+
 enum GeneratorID : u16 {
     Khronos = 0,
     LunarG = 1,
@@ -642,4 +644,4 @@ struct Instruction {
 Header header @ 0x00;
 
 // SPIR-V does not have any footer, increase number of instructions manually if you encounter a bigger shader
-Instruction instructions[1024] @ 0x14;
+Instruction instructions[while (!std::mem::eof())] @ 0x14;