Remove redundant macro definitions from curl_ext.c

Now that a hard copy of linux/list.h is restored in the obix package
itself, no external dependency on kernel-devel any more and the required
macros are always defined in that hard copy.
Cosmetic changes on the history.c

Remove redundant error messages, and printing out the content of
a bad formatted abstract node on error conditions
Cosmetic updates on README.md

The "-o cat" option should be used for journalctl to focus on the actual
messages instead of meta data such as timestamps
New test case to simulate how history index files are read

Add a new test case to simulate how history index files are read,
which can be used to evaluate the difference between xmlParseFile()
and xmlReadFile()

Turns out only the XML document generated by xmlParseFile can
support have its root subtree re-parented to another document.

At starts-up, the history subsystem will create a new node for
a history facility of a particular device under
/obix/historyService/histories/ and then read its index file and
reparent its root subtree to the previous node. So to this end,
only the xmlParseFile should be used so far.
Merge pull request #55 from Qingtao-Cao/devel

Devel