Windows safe filenames.

[jish]

cf. #241
cc: @mpapis @rlgreen91

In our template directory we were using ERB tags for filenames. These
filenames do not behave well in Windows environments. Instead of using
ERB replacement we are using simple token substitution.

[coveralls]

Coverage increased (+1.005%) to 97.26% when pulling 82bc896 on windows_safe_filenames into 3292193 on master.

[coveralls]

Coverage increased (+1.007%) to 97.263% when pulling 824ceb6 on windows_safe_filenames into 3292193 on master.

[coveralls]

Coverage increased (+1.005%) to 97.26% when pulling 4493b89 on windows_safe_filenames into 3292193 on master.

[mpapis]

sorry for late answer, jest this is a good fix, my guess is that %...% could be confused with dos variable evaluation, but I did not got chance to prove that, anyway this should fix it