Add steradian unit: solid angle
fixed the issue
improved dup_roots_upper_bound; what used to be counter t is now list t
fixed the min in dup_roots_upper_bound
added a line I had missed to copy
replaced tabs by spaces
"beautified" comments
more "beautification"; hope last commit
comments became green
changed variable Q to QL but problems still persist
returned code to original form; still do not see why does not pass Travis CI
Explicity set range for 2D line plot
Takes maximal span
Update plot.py
Update plot.py
Fix for the bug #7343
Fix for the issue #7342
Fix for the bug #7343

Corrected the bug by adding solutions returned from
each individual equation to the `sols` set. Previous
error was due to replacing the last solution in `sols`
by the new solution rather than appending it to the `sols`.
Fix for the issue #7342

Change the return type of `diop_solve()` to a tuple in the univariable
case. Also added the checks to ensure that only  `Add`, `Mul` or a
`Symbol` is processed in the `classify_diop()` function. Raised an
error in the other cases.
Replace `==` by `is`