Rename travis_test.sh to test_travis.sh

It was breaking ./bin/t<TAB> -> ./bin/test and it was driving me nuts.
Make test_travis.sh not executable
Changed default n to 6 in gruntz.calculate_series
Fixed the infinite rescursion.
Added an extra condition that takes an expression with an order term
so that the expression could be added to another order term without
reaching maximum recusion depth.
Merge branch 'master' of https://github.com/sympy/sympy into series-expand
Fixed import typo
Fixed an error
Merge branch 'master' of https://github.com/sympy/sympy into series-expand
Used dummy symbol, fixed the test
Add tests for issue #3626
Try to predict a correct number of taylor terms for function expansions with non-atomic argument, e.g. sin(sqrt(x)).series(x)
Fix test_code_quality.py failure: trailing whitespace in polytools.py
Merge branch 'master' into 3626
log(Product(...)) -> Sum(log(...))
Revert "Make test_travis.sh not executable"

This reverts commit 85886937514ae3d3f5105f45542d6d717ae03ee8.

Travis doesn't work if it isn't executable.
log(Product) -> Sum(log) requires simplify
log(Product(arg)) simplifies if arg.f.is_positive
Fix #3669: rsolve_hyper fails to find a solution if the characteristic equation has imaginary roots
Move tests for #2943 to test_rsolve_hyper() from test_rsolve()
Merge pull request #1774 from asmeurer/travis_test

Rename travis_test.sh to test_travis.sh