schema: introduce StringMap; kill MapType and ListType

schema: introduce StringMap; kill MapType and ListType

This makes it a lot more pleasant to deal with map[string]interface{}
types, which is by far our most dominant use of schema.

https://code.launchpad.net/~niemeyer/juju-core/schema-string-map/+merge/115849

(do not edit description out of merge proposal)

[niemeyer, 2012-07-19 22:34:12]

Please take a look.

[fwereade, 2012-07-19 22:45:02]

LGTM

https://codereview.appspot.com/6423062/diff/1/charm/meta.go
File charm/meta.go (right):

https://codereview.appspot.com/6423062/diff/1/charm/meta.go#newcode159
charm/meta.go:159: // defaults, which is different than what FieldMap can
well spotted :)

[niemeyer, 2012-07-20 00:02:28]

*** Submitted:

schema: introduce StringMap; kill MapType and ListType

This makes it a lot more pleasant to deal with map[string]interface{}
types, which is by far our most dominant use of schema.

R=fwereade
CC=
https://codereview.appspot.com/6423062