If type is not supported, throw exception not error
New array support templates. Now adding new array types is simple
Support for almost array types, need to be tested more precisely
Maybe type is added
Start creating simple analogue to QuickCheck. Templates behave like type
classes, it is amazing!
Lazy range generator
Arbitrary typeclass for integrals
Arbitrary for floating point
Arbitrary for bool
Arbitrary class for chars
Arbitrary for strings
Arbitrary for arrays
Finally, constrained checking function with shrinking
Major part of tests is finished.
Unused staff is removed
Scope clause was an obstucle to know what went wrong in unittest.
Merge remote-tracking branch 'origin/issue#25'

Conflicts:
	source/db/pq/types/array.d
	source/db/pq/types/conv.d
	source/util.d