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
Pretty printing of Integral(x, x)**2.

Wrap an Integral with brackets when raised to a power. Do the same
for most objects, excepts if it is an atom (doesn't need brackets)
or a function (which handle printing powers differently already).

Fixes issue 3260.
Remove a couple TODOs.
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
use subprocess module in preview.py instead of os.system
make preview function threadsafe again
added support for a few new kwargs to the preview function + cleanup
use more kwargs for SymPyDeprecationWarning
updated docstring
reworded docstring
fix test failures
removed call to sleep()
fix doctest error

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>