Adding benchmarks and prototyping cache functions.
Adding utilities, more benchmarks and testing a simple caching mechanism.
Finishing implementation of a simple cache. Generation time was reduced by a factor of 20% to 90% (according to attached benchmarks).
PostgreSQL: Updating sqlgen template declaration.
Adding caching for Statement struct.
MySQL: Updating sqlgen template declaration.
SQLite: Updating sqlgen template declaration.
QL: Updating sqlgen template declaration.
Merge branch 'feature/speed-improvements'

Conflicts:
	util/sqlgen/benchmark_test.go