deflate: add new deflate_quick strategy for level 1

deflate: add new deflate_quick strategy for level 1

The deflate_quick strategy is designed to provide maximum
deflate performance.

deflate_quick achieves this through:
    - only checking the first hash match
    - using a small inline SSE4.2-optimized longest_match
    - forcing a window size of 8K, and using a precomputed dist/len
      table
    - forcing the static Huffman tree and emitting codes immediately
      instead of tallying

This patch changes the scope of flush_pending, bi_windup, and
static_ltree to ZLIB_INTERNAL and moves END_BLOCK, send_code,
put_short, and send_bits to deflate.h.

Updates the configure script to enable by default for x86. On systems
without SSE4.2, fallback is to deflate_fast strategy.

Fixes #6
Fixes #8