Merge pull request #16 from robclewley/develop

Develop to master before Python 3 compatibility milestone
Merge pull request #19 from robclewley/develop

Major PyCont update (with new docs), sloppycell support, minor ModelContext/ModelConstructor fixes
Do not load full PyDSTool just for version number
Py3: fix deprecated form of raising exceptions

Warnings generated by `2to3`.
Py3: fix warning about 'map' with multiple arguments

Full `2to3` warning message:
    "cannot convert map(None, ...) with multiple arguments because map() now
    truncates to the shortest sequence"

While here, make 'dssrt.py' compatible with Python 3
Py3: fix '2to3' warning

Warning message:
    "You should use a for loop here"
Py3: 'setup.py' is ready for Python 3.3
Py3: use absolute imports
Adjust line endings for consistency
Py3: use absolute imports
Update .gitignore
Py3: use absolute imports (PyDSTool/Toolbox)
Py3: use absolute imports (PyCont)
Travis: bump latest NumPy version
Delete trailing whitespaces
Py3: use absolute imports (Toolbox/optimizers)
Adjust 'pytest' settings
Merge pull request #23 from robclewley/develop

Develop
Travis: specify branches to build
Makefile: remove temp dirs in 'examples' too