Improve Range handling

Add support for 416 and fix some corner cases.
Minor typo in varnishsizes' -P documentation
Typo
Remove varnishreplay from the index

Pointed out by geoff.
And remove rst file as well

sphinx complains otherwise.
Extend the type of argument and return value of V1L_Write

This allows adding up to ssize_t chunks
Improve systemd service units

Discussed with ingvar.
Replace the separate init/fini functions for the compiled VCL
with a single "event" function which takes the event as parameter.
Expand inifin mechanism to also handle events