implement now() as a generic function

[Mike Bayer]

No description provided.

[jek]

maybe these generics should live under a different namespace to minimize magic:

gfunc.now() # emits something to get a 'now' value, possibly crazy, crazy sql
func.now()  # emits now(), always

the namespace could be called anything, gfunc or generic, or ...

[Mike Bayer]

i think in the base func namespace we can put some conservative choices. I implemented now() in a0ffeb546468e14fa9d99b30571f7b8f9b32f421; the only change in behavior is that sqlite and oracle now produce "CURRENT_TIMESTAMP" whereas previously they'd just raise an error. other DB's should have the same behavior as before with now().

[Mike Bayer]

Removing milestone: 0.4.3 (automated comment)