v0.4.0

• Split ordered_map.h into ordered_hash.h, ordered_map.h and ordered_set.h.
• Move header files from src directory to tsl directory
• Reduce default max load factor to 0.75.
• Bug correction in equal_range, the second iterator was always equal to the first.
• Add methods taking a precalculated hash for lookups.
• Correct amount of reserved space for range insert.
• Use uint_least32_t instead of uint32_t for portability.
• Bug correction in 'iterator erase(const_iterator first, const_iterator last)`.
• Add insert_at_position, emplace_at_position and try_emplace_at_position methods.
• Correct method signature of emplace_hint.