Added missing const for cec_set_configuration argument

Method now matches prototype and is correctly exported for C.
Merge pull request #27 from kingosticks/fix/export-cec_set_configuration

Added missing const for cec_set_configuration argument
Merge remote-tracking branch 'pulse/master'
Revert "probably ugly hack to help with some"

This reverts commit 99c1cb2f69eadb6d4383b81d2edfbba91ddbde41.
re-apply of 99c1cb2f69eadb6d4383b81d2edfbba91ddbde41 to general handler
call unregister on close and set poll timeout to 3s