s1689: factor out common command-line options
s1689: add cookie identification method

Mostly plumbing to pass the new "cookie" argument down to the
Client objects. If present, the string is currently just
added as a CADC_SSO cookie to request headers to mimic the single
sign-on behaviour with browsers. For now the presence of a
cookie will override a supplied cert, since http will be used
(which is faster than https required for certs).
s1689: clean up logic/messages
s1689: missed a cookie
s1689: remove debug statement
s1689: fix bugs detected when running tests
s1689: fix loggers
s1689: fix vofile unit test

The tests were failing an "isInstance" assertion for the
Connection class. Rather than using the spec= argument (which
caused a different failure due to the cookie initialization),
use the actual Connection class and simply patch the get_connection
method.
s1689: tests for vos Client constructor
s1689: missed vrmdir in parser refactor
s1689: remove debug message
s1689: use scoped cookies
Make error messages more sepcific.

The client has some cases where failure to retrieve a file is not an error (retry),
those cases now report as a debug message.

There new '409' response code, which indicates a busy node, was changed to a different IOError.
Merge pull request #45 from edwardchapin/s1689

S1689: Add scoped cookie support to VOS clients
modified the module to be based from externally set SERVER/ENDPOINT vairables.  Added some documentation.

 The proc service endpoint is changing.  I pulled the server/endpoint information out of the methods and made them
 module level variables. These module levels variables are  over-ridden by environment variables from callers shell.

 These changes were needed to support migration of CANFAR to OpenStack.
made the cantop use the commonparser

vos.commonparser is where we put standard options like --verbose.  Also, this cleaned this up a bit.

cantop is still a bit weird as some of the customization is in the module and some of it is in the script...
Made the DELAY and RATE also be custom settable. And made call to vos.Client more generic.
added some clarifying text to correct the base documentation.