extend dynamodb2.table.query_count for more args
add simple test for query_count
Add method TaggedEC2Object.add_tags().

There is already a TaggedEC2Object.add_tag() method but it only supports
adding one tag at a time. The CreateTags api supports adding multiple tags
at once. So, when you want to add multiple tags you needlessly make multiple
round-trips to EC2 service. The add_tags method helps in avoiding that.
Fix behaviour of remove_tag when empty string is provided as value.

The documentation says that there is a distinction between a
value of '' and a value of None. The API docs say the same
thing. But the code was not following the docs:
    if value:
returns False for both None and ''.
Add tests for add_tag, add_tags, remove_tag methods of TaggedEC2Object
get_all_networkinterfaces() - add param to restrict lookup by list of ENIs
add update(), attach(), and detach() methods
add eni unit tests
Parse date/time in a locale independent manner

Creates a new threadsafe context manager to temporarily reset locale so that
strptime behaves as desired. Fixes #2271.
Reset locale after test run
Merge pull request #2317 from danielgtaylor/ts-locale

Parse date/time in a locale independent manner. Fixes #2317, #2271.
Install Travis language pack to fix tests
check scan_index_forward and limit are passed correctly for query_count
remove duplicate assert
Merge pull request #2311 from mtripoli/eni-enhancements

 Add network interface lookup to EC2. Add update/attach/detach methods to NetworkInterface object. Fixes #2311.
Merge pull request #2259 from mindprince/add_tags

Add method TaggedEC2Object.add_tags(). Fixes #2259.
Merge branch 'jamesonjlee-dynamodb2-query_count-attrs' into develop

Adds scan_index_forward and limit to DynamoDB table query count. Fixes #2184.

Conflicts:
	boto/dynamodb2/table.py
Fix failing test with updated import