feature #1712: Generic match-making functions. It can be used with any Resource and not just hosts
Merge branch 'master' into feature-1712
feature #1712: DatastoreXML class for the scheduler
feature #1712: DatastorePoolXML for scheduler. Load Datastore information to perform storage scheduling
feature #1712: Make Scheduler class more general to accomodate Storage Policies
feature #1712: Restructured scheduler main functions
feature #1712: Changed Match Resources Interface to accomodate Datastore scheduling
feature #1712: Fix memory leak
feature #1712: Basic DS scheduling in place
feature #1712: Rank for Datastores
feature #1712: Fix bug when scheduler template does not include policy attributes
feature #1712: Default for DEFAULT_DS_SCHED
feature #1712: Deployment and Migration API calls accept target system DS
feature #1712: Make use of datastore selection
feature #1712: Use constant for Cluster none
feature #1712: Couple host and system DS schedule
Merge branch 'master' into feature-1712

Conflicts:
	src/xml/expr_arith.cc
	src/xml/expr_bool.cc
	src/xml/expr_bool.h
feature #1712: Use cluster system DS. If no DS is specified in onevm.deploy the default SYSTEM_DS will be used.
feature #2289: monitor all VMs in EC2 IM

Get information from all EC2 instances in IM driver and provide
this information to OpenNebula so a VM poll is not executed per VM.
The monitoring will be much faster as VM is very expensive and the time
it takes to get info about one VM is very similar to getting information
about all VMs.

To keep track of the OpenNebula ID in EC2 machines a new tag is added
to EC2 instances (ONE_ID). This is used when monitoring VMs. VMs without
this tag wont be correctly reported to OpenNebula and will be monitored
with the old method (VM poll).

This version is kind of a PoC. The driver should be refactored so it
is similar to other drivers, that is, one script per action. The library
that holds the functionality will be held in a library file in VMM
driver as VMware drivers. Special care should be taken read
EC2 parameters as now is needed by both VMM and IM.
feature #2289: refactor ec2 drivers to standard form