Use .pem file if on windows

[inquam]

Instruct curl to use the needed .pem file if we are running on windows. The code checks for the .pem file in the same location as the BlockIo class file and if it's not found an exception will be thrown with ionformation about downloading the .pem file and where to palce it.

This gets rid of the need to alter php configuration files in order to get the library working on windows.

[patricklodder]

Thanks for this! I'll test this later today and will get back to you.

[inquam]

No problem, happy to assist

[doersf]

Thanks @inquam