flattened and simplified the if/elif/else statements in Qobj.__init__
removed unused imports. force Qobj.data for transposed object to be csr
refactored isherm, using property and property setter decorators
refactored isket, isbra, isoper, issuper to be Qobj properties
ischeck -> _typecheck
remove unneeded copy
make tidyup act on self instead of creating a new object
added __abs__ method to Qobj, defaulting to the __abs__ of the Qobj instance data attribute
minor bugfix in visualization.hinton (undefined variable fig in some cases)
use cy_expect_psi in sesolve
fixed bug with using TextProgressBar in mcsolve when ntraj is a list
changed argument to TextProgressBar for ntraj as list
made qobj.type a dynamic property (since it always can be computed from the dims attribute). attempt to fix bugs reported by @cgranade in #96
do not need to set Qobj.type anymore
made shape a property, since it can always be computed from the dims attribute
no need to specify shape anymore
avoid unnecessary copy operators
keep track of superrep value when carrying out operators on Qobj instances. Updated docstrings.
updated docstrings
pep8 fixes