Update installation.rst
Update installation.rst

Casperjs on Windows has changed in 1.1beta3: it used casperjs.bat in directory batchbin, it now uses casperjs.exe in bin. Need to keep both as long as the last stable version still uses the old batchbin.
jefleponot/casperjs,casperjs/casperjs,jefleponot/casperjs,hlr1983/casperjs,casperjs/casperjs,mickaelandrieu/casperjs,hlr1983/casperjs,jefleponot/casperjs,hlr1983/casperjs,istr/casperjs,mickaelandrieu/casperjs,hlr1983/casperjs,mickaelandrieu/casperjs,mickaelandrieu/casperjs,mickaelandrieu/casperjs,casperjs/casperjs,istr/casperjs,casperjs/casperjs,n1k0/casperjs,istr/casperjs,istr/casperjs,n1k0/casperjs,casperjs/casperjs,casperjs/casperjs,n1k0/casperjs,jefleponot/casperjs,istr/casperjs,hlr1983/casperjs,hlr1983/casperjs,mickaelandrieu/casperjs,jefleponot/casperjs,istr/casperjs,n1k0/casperjs,n1k0/casperjs,n1k0/casperjs,jefleponot/casperjs