Fix call site when using Pool.prototype.query

This fixes the call site for long stack traces when using the query
method on a pool object. Before the stack trace would only lead up
to inside the getConnection method instead of the library caller.
docs: Remove createConnection options from Pool options
crypto.createHash fix for node.js < 11
Merge pull request #735 from jas-/crypto-fix

crypto.createHash fix for node.js < 11
2.1.0 changes
2.1.0
Merge pull request #715 from dougwilson/fix/pool-long-stack-trace

Fix call site when using Pool.prototype.query
add example of using pool directly
Merge pull request #739 from coderhaoxin/master

add example of using pool directly
Merge branch 'master' of https://github.com/felixge/node-mysql