Python 3.x support for %mprun.

I also added supported Python versions to setup.py explicitly.
IPython error message is fixed
bikeshedding (style fixes):

- PEP8 spaces for inline comments;
- more meaningful variable names instead of `a,b=Pipe()` (taken from Python docs);
- don't shadow builtins 'dict' and 'dir' with local variables;
- remove unneeded indentation;
- use 'with' for opening files
Merge pull request #35 from kmike/mprun-py3k

Python 3.x support for %mprun.
Merge pull request #37 from kmike/small-fixes

Small fixes
FIX #36
Merge remote branch 'fabianp/master'
Plotting of mprofile output

The "mplot" script has been added. Plots of memory consumption can
be done with it.
Added -o option to memory_profiler

Output of 'python -m memory_profiler -o "bar.out" script.py' goes
into file "bar.out" instead of standard output.
Added mplot to setup.py
Added timestamping feature

Added a --timestamp option that when turned on, output timestamps
for start and end of every decorated function, instead of memory
profile.
This options is intended to be used together with the mprofile script,
to be able to plot the lifetime of some functions  on the global
memory graph.
Timestamping is handled by mprofile and mplot

An --python option has been added to mprofile, just to add the proper
timestamping options to the run python program.
mplot now looks for a timestamp file, and plot the additional
information as vertical lines.