Use ROOT6 banner.
Use the new banner properly; improve footer, search style.
fRenderer, the TMathText Painter, should not be stored.
Fix https://sft.its.cern.ch/jira/browse/ROOT-6259
Reduce the number of Flush (fsync) when closing a TFile.

Rather than doing one call to Flush (fsync) per TDirectory during the execution of TFile::Close
we reduce this to just one call.  Doing so many sync was extremely slow on an ATA disk (order
of 5 minutes for 90000 TDirectories.  With this update the time is down to half a second.
Check for tab container existence, see ROOT-6253.

(cherry picked from v5-34-00-patches commit 05790b6f1f099c1aa43f5146d4c08bff2612adf0)
Fix for https://sft.its.cern.ch/jira/browse/ROOT-5817 (configure checks for freetype-config but then ignores it for #includes)
Formatting....
Fix 2 bugs appearing as a side-effect of the previous fix:

- when cloning fBinHist -call SetDirectory(0) since the TH1(2)Editor manage the histogram
- add the TH1(2)Editor must be registered in the list of cleanups so the contained fHist pointer is set to zero when the referred histogram is deleted
Fix input files processing (cling foo.c should work now)
Adding test for ROOT-6244 (test_exec_in_same_dir.C)