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
lxml instead of libxml2 for c2p, google app engine supports lxml and generally better supported
empty line made quality test fail
apply_xsl real doctest instead of just usage example
doctest_depends_on added, doctest corrected
Addition of hypertangent and exponential cases to parametric differntial equations

 added code exponential for to special denom

added code for tangent cases to special denom

added code for tangent cases to special denom

First attempt to solve the section 5.12

first attempt to solve section 5.12 and related problems

First Attempt to implement section 5.12 and related problems

added hypertangent test cases for param special

deleted binary file
tested from within vim line-by-line over more files and missed import line in this file
Make isympy importable in Python 3

That way, if someone runs python3 bin/isympy, they will get the "this is the
Python 2 version of SymPy" error message instead of a SyntaxError.
Drop str() printers for factorial/subfactorial/etc (issue 3781)
Fix tests for factorial printing (issue 3781)
Fix docstring tests for factorial printing (issue 3781)
Change signs in test for issue 2934
as_real_image not working as expected
real_img function in prde.py

This commit enables us to evaluate real and imaginary parts of multivariate polynomials
Given numerator and denom of a function and the generator, it converts the poly into a dict with the degree of DE.t as the key
and the cofficients(corresponding to the degree of the variable) as the value. Inturn it seperates
the degrees with respect to mod 4
Sort output of dotprint according to args ordering

This makes the output to the dotfile use this ordering (previously it used
len), and also adds the ordering="out" flag to the file (see
http://stackoverflow.com/a/9216782/161801).

I didn't add a way to change the ordering.  The previous one, len, would
roughly order the nodes from biggest to smallest, but not exactly, since it
was a len on the string rather than a len on the nodes.
added code exponential for to special denom

added code for tangent cases to special denom

added code for tangent cases to special denom

First attempt to solve the section 5.12

first attempt to solve section 5.12 and related problems

First Attempt to implement section 5.12 and related problems

added hypertangent test cases for param special

Also solves the previous issues:
-> General code cleanup
(spaces after commas, spaces around operators, more even line wrapping in the docstring).
-> Seperates the real and imaginary parts to prevent param_log_deriv_heu faliure
(Avoids faliure due to complex extenions by using real amd imag parts seperately)
-> All unification error are avoided
(A major problem in previously failed commits)
->Add doc string to real_img
(Puts a description to the real_imag function in prde.py)
Some updates/cleanups to the README