daid/Cura — pull request #989 by brad (2014-10-20 00:11:59+00:00)
Title: avoid TypeError when reading the active io

I ran into the following error while trying to slice with the current code on a raspberry pi running Debian:

```
Traceback (most recent call last):
File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main
"__main__", fname, loader, pkg_name)
File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
exec code in run_globals
File "/home/brad/projects/Cura/Cura/cura.py", line 89, in
main()
File "/home/brad/projects/Cura/Cura/cura.py", line 77, in main
data = gcode.read()
File "Cura/util/bigDataStorage.py", line 25, in read
ret = self._active.read(size)
TypeError: an integer is required
```

This PR is my proposed solution to fix the problem.