[PHPLIB-112] Configurable type map for findAndModify and non-cursor aggregate commands

[jmikola]

https://jira.mongodb.org/browse/PHPLIB-112

[jmikola]

Benchmark script: https://gist.github.com/jmikola/a6efe8d512615f36b7c6df87951fd4a2

Profiles:

• Large nesting (625 sub-documents under "c" field)
  • Without typeMap conversion: 20.9s / 2.28MB
    https://blackfire.io/profiles/496dfa88-e27d-4464-bb46-06beb60d7543/graph
  • With typeMap conversion: 44.6s / 5.63MB
    https://blackfire.io/profiles/5873e5a6-3341-4b94-9117-c2c68c75002a/graph
• Small nesting (5 sub-documents under "c" field)
  • Without typeMap: 11.7s / 1.51MB
    https://blackfire.io/profiles/b2c76263-d6e6-4f46-8869-eb3ecc8dc554/graph
  • With typeMap: 20.4s / 3.71MB
    https://blackfire.io/profiles/6d780d08-9fdf-448c-98d7-1171aaff0e28/graph

Comparing large nesting, the typeMap option adds 113% execution time and and heavily waited in the toPHP() call (17.2s vs. 4.85s spent in fromPHP()). This is likely due to each sub-document requiring a new BSONDocument construction and call to BSONDocument::bsonUnserialize().

Comparing small nesting, the typeMap option adds 74.9% execution time and is roughly split evenly between fromPHP() and toPHP() calls.