Tangelo attempts to create the logfile directory if it does not exist, and prints an error message if something goes wrong

Closes #246
Merge branch 'create-logdir'
Changed "localhost" to "0.0.0.0" in example config files

Closes #247
Merge branch '0.0.0.0'
Eliminated second argument ("defaultValue") from tangelo.accessor()

Closes #259
Merge branch 'no-accessor-default'
Added finer controls over what gets built.

Closes #253
Merge branch 'finer-cmake-control'
Bundling ws4py with Tangelo (since its version is <1.0)

Closes #255
Merge branch 'bundle-ws4py'
Improvements to the clientside steraming functions

Streaming callbacks now receive data and "finished" flag separately.

DELETE verb for streams now sends back the deleted key instead of the word "OK".

Closes #260
DELETE action on VTKWeb now returns the deleted key.

This is the same improvement made to the streaming REST API in commit
6c2b2b72cfc3418923cc38311e1891d6e5c1e9d5.
Merge branch 'improve-streaming'
Marking BUILD_TANGELO as advanced

Closes #253
Merge branch 'hide-build-tangelo-option'
More informative error message in vtkweb-launcher.py

(Via zack.galbreath@kitware.com)
Merge branch 'informative-import-error'
Restructured CMakeLists to handle new testing infrastructure
Added Javascript unit testing infrastructure.

Jasmine is used to specify the unit tests, and PhantomJS runs the tests.  CMake
generates test suites by embedding various .js files found in
testing/js-unit-tests, into an HTML scaffold that includes code to take the test
results and report them nicely in HTML.  These files are placed in Tangelo's
default web space, and CTest generates invocations of PhantomJS to "run" the
tests using a modified run-jasmine.js.

Eventually, each test will need to depend on a test that launches the Tangelo
server.  There will be a similar teardown "teardown" test that will depend on
all of the other tests.  This will work somewhat differently on Windows, since
there isn't an option to launch Tangelo as a daemon there.
Added "web content testing" infrastructure, along with several content tests.

Removed some of the "old style" content tests (when they were able to be
replaced by new style ones).

Dumped "resolve" test.

Updated two of the test services to better format their results (better use of
spaces and newlines).