Add a couple of asserts to explain stuff to Coverity
VRY_Len() returns only the length of a single entry in the VRY spec,
for conditional fetch-copying, we need the length of the full VRY-spec.

Fixes:	#1350
Spot and handle 3-digit status from backend, where the first digit is zero.

Fixes:	#1337
Make this test a comprehensive test of the status parsing
Break line longer than 80 characters
Fixup docs based on feedback.
Fix error handling code and typo when parsing -IX flags

Spotted by: Coverity
Check return value from VSB_finish

Spotted by: Coverity
Add break after WRONG() assertion to silence Coverity
Rename variable to deconfuse Coverity
Be more thorough the testing streaming+restart

Reset vfp when restarting in deliver, in case it has be set in
cnt_fetchbody already.

Fixes: #979

Conflicts:
	bin/varnishd/cache_center.c