less: Fix issues with the map file on Windows. See the comment in the code for more information. Also, only wrap the opening of the map file in a try/except clause, since we want to catch the situation where the map file is missing only.

sudo: false
language: python
python:
  - "3.4"
install:
  - "pip install -r requirements.txt"
  - "pip install -r dev-requirements.txt"
script: py.test