HTTP(S) and WEBDAV access now goes via TDavixfile/TDavixSystem.

These classes make use of the libdavix library and coded
by Tigran Mkrtchyan (DESY) Fabrizio Furano (CERN) and Adrien Devresse (CERN).
fix coding style and indentation.
don't print an Error when we can't load libRDAVIX in plugin script.
check return value of setresuid(). Fixes ROOT-5816.
make sure compiler specified in ./configure is used. Fixes ROOT-5818.
Add additional protections when dealing with source ranges.
Correct typo in variable name resulting in missing part of the commandline
If no module name present, deduce one from the dictname

and use it to construct a name for the rootmap.
ROOT-5819 rename offset calculation parameter from <target> to <base>.

(cherry picked from commit f3cf5e96c4c922f74df33f78e3df926a9ce2f0fb)
Add test for Interpreter::compileFunction().
Modified makeonepcm.sh script and related files to make it work for CMake. It fixes ROOT-5822.
Ensure that unuran uses the same compiler (CMake). Fixes ROOT-5818
next generation xrootd client (libNetxNG). Requires xrootd >= 3.3.5.

Provided by Justin Salmon, Lukasz Janyst (CERN/IT).
Fix the system.plugins-ios to use the TWebFile instead of davix.

Davix not yet on iOS.
silence another warning coming from the xrootd headers.
Added davix package (CMake). Addresses ROOT-5826
call assignment operator instead of memcpy on data member assignment
Fix: http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=17404
#circ was not rendered correctly
fix ROOT-5824