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.
Piecewise._eval_interval for cond. indep. of integration var.

This fixes the Integral of a Piecewise when the conditions are
independent of the integration variable.

Before:

>>> integrate(Piecewise((0, Eq(y, 0)), (x*y/sqrt(y**2), True)), (x, 1, 3))
4*y/sqrt(y**2)

After:

>>> integrate(Piecewise((0, Eq(y, 0)), (x*y/sqrt(y**2), True)), (x, 1, 3))
Piecewise((0, y == 0), (4*y/sqrt(y**2), True))
Changed default n to 6 in gruntz.calculate_series
Fix issue 3649

The problem was that Integral._eval_subs was returning an instance of
Integral, so that NonElementaryIntegral.subs() was returning an instance of
Integral, and hence failing an isinstance check. I changed all methods of
Integral to use self.func(*args) instead of Integral(*args).  But we need to
audit all of SymPy and make sure we are doing this everywhere.  See issue
3652.
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
Fix tests in Python 3.3 with --no-subprocess

See issue 3629.  Test by running ./bin/test --no-subprocess in Python 3.3.
Merge branch 'master' of https://github.com/sympy/sympy into series-expand
Used dummy symbol, fixed the test
Update wiki references (point to githib/wiki)
Merge branch 'master' into old-wiki-refs
Merge branch 'master' into remove-old-wiki-refs
Drop references to
https://github.com/sympy/sympy/wiki/old-wiki-Sympy-Development
Drop obsoleted refs to
https://github.com/sympy/sympy/wiki/old-wiki-Discussion
use subprocess module in preview.py instead of os.system