UX improvements for Launch Instance dialog

This patch solves two UX issues on the Networking tab
of Launch Instance dialog:

1) "nic" is lowercase when the acronyms usually are capitalized.
2) "Selected Networks" and "Available networks" do not follow
the same capitalization convention.

Change-Id: If83f605dc2ebbfd408811634da2bad231356f057
Closes-Bug: #1325684
APIDictWrapper getitem lookups fail for non str

The APIDictWrapper class within openstack-dashboards/api/base.py can't
handle the "in" operator correctly.

Also, it will fail if a non-string is passed into it's __getitem__
method. (Which is what is called from a dict lookup.)

The get method also fails on non-strings.

Change-Id: Iaad66d3c6deb81d0570b1a8c6ddf580024fa46e6
Closes-Bug: 1326512
Handle error from neutron extension check in Overview page

Previously some Neutron API calls in get_neutron_limits are outside
try/except and if an error occurs a traceback will be displayed.

Change-Id: I191aecbf3135ddac3b20dbc7e0f22b63aa3837f9
Closes-Bug: #1252878
Merge "UX improvements for Launch Instance dialog"
Merge "APIDictWrapper getitem lookups fail for non str"
Merge "Handle error from neutron extension check in Overview page"