New test for upcasting newints to floats.
Added upcasting test for complex numbers
Fixing upcasting behaviour for some operations on integers.
Some cleanup
Removing some magic method, making others more stable.
Added tests for bitwise operations and some more arithmetics.
Test for unary operators
Restoring behaviour of __div__ and consorts
Merge branch 'krischer-master'
Bump version number to v0.12.4-dev and add a What's New section