netbios type should be coerced to integer.

Otherwise the check always fails.
VPCs can now be filtered by id.
VPCs can now be filtered by cider block and dhcp options id
Added the ability to filter vpcs by tags.
allow get_filter_value to return state of ami and test

  * updated Ami.get_filter_value to return the state value of the AMI
  * updated test_ec2.test_amis.test_ami_filters to test for AMIs in the state of 'available'
Test Fixes and `tag:` filter.

  * fixed test_ec2.test_amis.test_ami_filters to test for AMIs in the state of 'available'
  * enhanced AMI's to be able to take `tag:` filter.
  * added tag: tests for AMIs
Merge pull request #214 from thedrow/patch-2

netbios type should be coerced to integer
Merge pull request #219 from joekiller/ami_filter_state

allow get_filter_value to return state of ami and test
Tests will now pass on Python 3.3.
Merge pull request #218 from thedrow/feature/vpc-filters

Added the cider block, dhcp options id and tag filter to the VPC backend
Added the ability to filter by tag-key.
Added the ability to filter by tag-value and refactored the filters to be generic.
Merge branch 'feature/vpc-filters'
Added tag filters to some of the entities.
Merge pull request #221 from thedrow/topic/filters

More tagging filters and refactorings
Update BaseResponse to keep blank values of keys when parsing the url.

  * Amazon treats blank values as empty strings, ie http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-CreateTags.html
Added more complete tags implementation

Tags
===

refactored tags to be able to apply a dictionary of tags as specified in http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-CreateTags.html

  * create_tags and delete tags validates resource ids
  * create_tags ensures that resources exist prior to tagging
  * fixed delete tag rendering unncessary template
  * Update describe_tags to use filters from querystring

Exceptions
 ======

  * Added InvalidID exception used by CreateTags and DeleteTags per http://docs.aws.amazon.com/AWSEC2/latest/APIReference/api-error-codes.html#InvalidID
  * Added TagLimitExceeded per http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-CreateTags.html

Models
=====

  * Added validate resource ids method which will throw a InvalidID exception if the resource_id form is incorrect
  * Renamed TaggedEC2Instance object to TaggedEC2Resource, updated all inheritance references.
  * Added TagBackend create_tags method
    * Updated TagBackend create_tags to throw InvalidParameterValueErrorTagNull if a CreateTag key doesn't include a value
    * Updated TagBackend create_tags to throw TagLimitExceeded
  * removed TagBackend create_tag and delete_tag functions
  * Added TagBackend delete_tags method
    * Updated delete_tags method to allow key/value delete per http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-query-DeleteTags.html
  * Updated SpotInstanceRequest to allow filter_name 'spot-instance-request-id'
  * Enhanced EC2 Model to allow for checking of if a resource exists based on the resource_id.  This is necessary because tag creations verify that a resource exists prior to performing any action.
  * Updated create_tags method to check if len(tags) > 10 and raise TagLimitExceeded even if the resource doesn't have any tags.
  * Updated TaggedEC2Resource to pass in a proper filter dictionary to describe_tags
  * Updated Instance get_tags to pass in proper filter dictionary to describe_tags
  * Updated TagBackend to properly filter response based on filter dictionary

 EC2 Utils
 ======

  * Added EC2_RESOURCE_PREFIXES to help with parsing prefixes in resource_ids
  * Updates random_[resource] functions to use EC2_RESOURCE_PREFIXES dictionary
  * Updated tags_from_query_string to return a dictionary of tag keys and tag values.
  * Added get_prefix method to help with determining resource types from EC2 resource_ids
  * Added is_valid_resource_id method to determine if a resource_id is valid for EC2 resources
  * Renamed EC2_RESOURCE_PREFIXES dictionary to EC2_RESOURCE_TO_PREFIX
  * Added EC2_PREFIX_TO_RESOURCE dictionary which is EC2_RESOURCE_TO_PREFIX inverted.
  * Added simple_aws_filter_to_re method for converting AWS wildcard syntax keys to python regular expression matches

Test Tags
======

  * Renamed various tag test names to be more relevent
  * Added test to raise InvalidParameterValue when a tag key is None
  * Added test_tag_limit_exceeded
  * Added test_get_all_tags_resource_id_filter to test get_all_tags using resource-id filter
  * Added test_get_all_tags_resource_type_filter to test get_all_tags using resource-type filter
  * Added test_get_all_tags_key_filter to test get_all_tags using key filter
  * Added test_get_all_tags_value_filter to test get_all_tags using value filter