Fix LLVMRevision source URL in cpt.py

LLVMRevision is being retrieved from an old URL, which contains the wrong LLVM revision. Update it to point at the current cling repository.
Fix Markdown formatting and update CPT link.
Add a Travis-CI driver for github builds.
Checkout cling patches.
Add link to the last travis build result.
Recompile once more due to the little travis resources.
Use the fully qualified name.
reference REPL is a way most people will recognize
Protect from skipping function template patterns.
Handle member fun ptr (ROOT-5467).
Add test for ROOT-5467.
Also do a make install before testing.
Speed up the test builds. Run make install in the root build dir.
No new lines on the config line.
Use check_call and check_output for subprocess
Remove empty spaces.
Mark as XFAIL until Axel fixes it.
Make Python scripts Python3-compatible