Issue 3289: substitute warnings for print statements
change print to warning. missing import statement
Merge remote-tracking branch 'upstream/master'
fixed warnings statements in pretty_symbology.py
Fix issue #879: series of undefined functions.
Issue 879: add test for series of a subclass of Function.

Now we can use also

    >>> class TestF(Function):
    ...     pass
    >>> TestF(x).series(x)
Issue 879: fix python3 failure.
Added dot product tests from different frames.
Minor Fix.
Added print statements and modified assertion tests
Added correct print statements
Assertion tests satisfying new trigsimp changes
Split physics.mechanics examples into multiple files.
Edited the docstring for ReferenceFrame.orient().
Merge branch 'mechanicsdoc'
lxml instead of libxml2 for c2p, google app engine supports lxml and generally better supported
Changed title to be consistent with other Physics/Mehcanics titles.
Got bicycle example working by adding a q3 dynamicsymbol.
Gave the rolling disc image a more descriptive file name.
Gave the rolling disc image a more descriptive file name.