state/api/agent: Entity stores a names.Tag internally
state/api/machiner: store a names.Tag internally
more string -> names.Tag
more string -> names.Tag
remove another must method
remove another must method
remove another must method
Fix compiler crash
gofmt
Merge pull request #151 from davecheney/113-fix-gccgo-crash

Fix compiler crash
environs/instances: expose getMatchingInstanceTypes

The azure provider has some custom instance-type
matching code which can be made to use this function
if it's exposed.
Merge pull request #148 from axw/environs-instances-matchinginstancetypes

environs/instances: expose getMatchingInstanceTypes

The azure provider has some custom instance-type
matching code which can be made to use this function
if it's exposed.

Also, move instance-type constraint matching into `MatchingInstanceTypes` and friends, simplifying `FindInstanceSpec`.
Merge pull request #145 from davecheney/111-api-params-takes-tag

params.Entity preparations

This PR is a grab bag of changes aimed at isolating all the places where we pass a string to params.Entity and convert them into taking a names.Tag. 

This PR isn't complete, there is still more work to be done before params.Entity.Tag can be made into a names.Tag, but it is a good checkpoint as it gets rid of all the mustParseXXX methods added in a previous PR.
provider/azure: simplify role size selection, report hardware, fix costs

- Use the newly exported environs/instances.MatchingInstanceTypes
  to simplify instance type selection when force-image-name is used.
- Update role costs and role sizes (bump gwacl rev).
- Emit hardware characteristics by converting gwacl.RoleSize to
  instance.HardwareCharacteristics.

Fixes https://bugs.launchpad.net/juju-core/+bug/1215177
Merge pull request #152 from axw/azure-instance-types-update

provider/azure: simplify role size selection, report hardware, fix costs

- Use the newly exported environs/instances.MatchingInstanceTypes
  to simplify instance type selection when force-image-name is used.
- Update role costs and role sizes (bump gwacl rev).
- Emit hardware characteristics by converting gwacl.RoleSize to
  instance.HardwareCharacteristics.

Fixes https://bugs.launchpad.net/juju-core/+bug/1215177