Revert "[core] implement streams on chunkqueues"

 - accidental push, patch not finished yet

This reverts commit 74ce55c86061f6110964d7de0cd5adc5f4ccfb57.
[tests] add --valgrind option
[core] implement streams on chunkqueues
generic backends
[core] Use streams
[mod_fastcgi]: use backends
[mod_scgi] use backends
[common] implement libev wrapper

 * need a way to mark a watcher as "don't keep the loop alive"
[mod_proxy] use backends