Windows platform support: Convert double backslash to single backslash
Windows platform support: Convert double backslash to single backslash

See #2550 and https://github.com/Codeception/Codeception/pull/2551#issuecomment-167756694
TehJoE/Codeception,tasselchof/Codeception,Codeception/Codeception,janhenkgerritsen/Codeception,Codeception/base,Naktibalda/Codeception,Naktibalda/Codeception,janhenkgerritsen/Codeception,Codeception/base,pitpit/Codeception,pitpit/Codeception,tiger-seo/Codeception,Vreasy/Codeception,Codeception/base,tasselchof/Codeception,hubbyist/Codeception,sergeyklay/Codeception,Naktibalda/Codeception,kt81/Codeception,sergeyklay/Codeception,Vreasy/Codeception,tasselchof/Codeception,TehJoE/Codeception,kt81/Codeception,tiger-seo/Codeception,hubbyist/Codeception,Codeception/Codeception