Initialise objType and objState explicitly in new rods paths.

Initialise results of list_collection explicitly.
Separate the listing of collections and the listing their contents
into distinct types of operation.
Updated required software versions.
Merge pull request #81 from keithj/devel

Separate the listing of collections and the listing their contents
Moved collection contents to be a property of a collection. Thus we
can always return a JSON object as the outer container.
Use the optional collection path as a zone hint in metadata queries.
Merge pull request #82 from keithj/devel

Use the optional collection path as a zone hint in metadata queries.
Added a regression test and fix for github issue #83. Fixes #83.
Fixed a memory leak identified by valgrind.
Added test file for regression test.
Moved free to avoid a double free error when the user supplies an
invalid operator.
Updated manual.
Merge pull request #84 from keithj/devel

Added a regression test and fix for github issue #83. Fixes #83.
Merge branch 'devel' of github.com:wtsi-npg/baton into devel
Added URL of online manual.